Care basicsTM-12
Tropical Fish for Beginners: How to Choose Fish, What You Need, Typical Costs and the First Month
Tropical fish are easiest to start with when you add small, peaceful fish a few at a time to a tank that has already been cycled.
In this article (17 sections)
- In short: which tropical fish should beginners start with?
- How do you choose tropical fish for beginners?
- Why do these 7 species suit beginners?
- Which fish should tropical fish beginners leave for later?
- What size tank should tropical fish beginners start with?
- What do tropical fish beginners need?
- How much does it cost to start keeping tropical fish?
- What are the monthly costs of keeping tropical fish?
- How should tropical fish beginners plan the first month?
- How many fish should tropical fish beginners add at first?
- What daily and weekly care do tropical fish need?
- What mistakes do tropical fish beginners often make?
- What should tropical fish beginners do when a fish looks unwell?
- What terms come up when starting with tropical fish?
- What else should tropical fish beginners read?
What do beginners often ask about tropical fish?6
- Sources
In short: which tropical fish should beginners start with?
Beginners find small, peaceful fish the easiest to handle. Good candidates include neon tetras, harlequin rasboras, platies and corydoras.
Shop guides and rankings also often name neon tetras and guppies as first fish. The reasons are almost always "hardy," "cheap" and "peaceful."
But sources draw the line for "hardy" in different places. This site lines up the care data for each fish, so you can see the reasons behind each choice.
What this article covers:
- How to compare 7 beginner species by size, temperature and temperament
- Fish to leave for later, and why
- What you need, and typical start-up and monthly costs
- How the first month goes, and the order to add fish
- Common mistakes, and what to do when fish look unwell
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | |
|---|---|---|---|---|---|---|---|
| 1Neon tetra | · | ○ | ○ | ○ | ○ | ○ | ○ |
| 2Harlequin rasbora | ○ | · | ○ | ○ | ○ | ○ | ○ |
| 3Cherry barb | ○ | ○ | · | ○ | ○ | ○ | △ |
| 4Platy | ○ | ○ | ○ | · | ○ | ○ | ○ |
| 5Guppy | ○ | ○ | ○ | ○ | · | ○ | △ |
| 6Panda cory | ○ | ○ | ○ | ○ | ○ | · | ○ |
| 7Cherry shrimp | ○ | ○ | △ | ○ | △ | ○ | · |
○ Generally compatible △ With care × Not recommended
Source: Judged by this site's rules from the care data of each species (see the sources of the care data table)
The quick chart above shows compatibility for fish and shrimp often recommended to beginners. Every fish-to-fish pair is ○, and the only △ are pairs with the shrimp.
| Pair | Compatibility | Reason |
|---|---|---|
| Cherry barb × red cherry shrimp | △ | Sometimes chases adult shrimp |
| Guppy × red cherry shrimp | △ | Eats baby shrimp. Adult shrimp survive |
| Neon tetra × red cherry shrimp | ○ | They like similar water |
| Platy × panda corydoras | ○ | They use different levels, and both are peaceful |
Here are three example setups for a first tank. In each one, every pair comes out ○ in our calculation.
| Setup | Top | Middle | Bottom |
|---|---|---|---|
| A: Watch a school | None | Neon tetra | Panda corydoras |
| B: Enjoy the colors | Platy | Harlequin rasbora | Panda corydoras |
| C: Keep shrimp too | None | Neon tetra | Panda corydoras and red cherry shrimp |
The key point: for beginners, the order matters more than the choice of fish: cycle the tank first, then add fish a little at a time.
How do you choose tropical fish for beginners?
Choose by size, water temperature, temperament and group size. Sources do not describe hardiness in a consistent way.
Seriously Fish species pages have a field for hardiness. But for the neon tetra and the guppy, that field says "unknown."
So this site compares values you can check in the sources.
| What to look at | Better for beginners | Reason |
|---|---|---|
| Adult size | Small, with a small mouth | Does not eat other fish, and fits the tank |
| Temperature and pH range | Wide | A small drift puts less strain on the body |
| Temperament | Peaceful | Less chasing and fin nipping |
| Group size | A number that fits the tank | Schooling fish settle once there are enough of them |
| Origin | Farmed fish | Adapt to aquarium conditions more easily than wild fish |
| Species | Adult size (cm) | Temperature (°C) | pH | Swimming level | Temperament | Group size (or more) |
|---|---|---|---|---|---|---|
| Neon tetra | 4 | 21–25 | 4–7.5 | Middle | Peaceful | 8 |
| Guppy | 6 | 17–28 | 7–8.5 | Top | Peaceful | 3 |
| Platy | 6 | 20–26 | 7–8.2 | Top | Peaceful | 3 |
| Panda cory | 5 | 22–25 | 6–7.4 | Bottom | Peaceful | 6 |
| Harlequin rasbora | 5 | 21–28 | 5–7.5 | Middle | Peaceful | 8 |
| Zebra danio | 5 | 18–25 | 6–8 | Middle | Peaceful | 8 |
| Cherry barb | 5 | 20–27 | 6–8 | Middle | Peaceful | 6 |
Source (7)
All 7 species in the table are peaceful and stay small as adults. As the table shows, their temperature ranges share an overlap.
For pH, the platy and the guppy prefer water above neutral. If you keep them with neon tetras or rasboras, the shared range is around neutral.
Beginners find it easier to choose if they look first at the "temperature overlap" and the "group size" in the table.
Why do these 7 species suit beginners?
Sources describe all 7 as peaceful and easy to keep. But each one has its own points to watch.
| Fish | Why it suits beginners | What to watch |
|---|---|---|
| Neon tetra | Most fish on sale are farmed, so they adapt more easily than wild fish | Long farming has weakened some fish. Choose lively ones |
| Harlequin rasbora | A fish you can recommend without hesitation to first-time keepers | Kept in a school, so the tank base should be at least 60 cm wide × 30 cm deep |
| Cherry barb | A peaceful fish you can recommend to beginners without hesitation | Sometimes chases adult shrimp |
| Platy | Peaceful, and can live with many fish | Prefers fairly hard water, and does poorly in acidic soft water |
| Guppy | Peaceful, and swims near the top | Shop fish are sometimes weak from inbreeding |
| Panda corydoras | Lives on the bottom, apart from the other fish | Sensitive to poor water. Keep the substrate clean |
| Zebra danio | Hardy and reasonably priced | Swims a lot, so the tank base should be at least 90 cm wide × 30 cm deep |
The "why" and "what to watch" columns come from each species page on Seriously Fish.
Guppies and platies breed readily in aquariums. If you do not want them to breed, Seriously Fish suggests keeping only one sex.
Before you put males and females together, decide what you will do with the fry. If you are unsure, starting with one sex is the safe choice.
Even among "beginner fish," conditions differ: the platy wants fairly hard water, and the zebra danio a larger tank.
Which fish should tropical fish beginners leave for later?
Leave fish that grow large, aggressive fish and fish sensitive to water quality for later. They suit a tank that has settled.
| Fish | Why leave it for later | Source |
|---|---|---|
| Betta (male) | Best kept alone. Not suited to a community tank | Seriously Fish |
| Angelfish | As it grows, it may eat small fish such as tetras | Seriously Fish |
| Tiger barb | Nips the fins of other fish | Seriously Fish |
| Cardinal tetra | Wild-caught fish are sensitive to poor water | Seriously Fish |
| Otocinclus | Almost all are wild-caught and sensitive to water quality | Seriously Fish |
| Bristlenose pleco | Grows large and fights similar-shaped fish over territory | Seriously Fish |
| Goldfish, medaka | Fish that need no heater, with a different suitable temperature | RSPCA, Seriously Fish |
Seriously Fish writes this about otocinclus: they have fewer problems when added to a settled tank with plenty of plants.
The betta is an easy fish to start with in a tank of its own. Partners for bettas are covered in Betta Tank Mates.
"Later" does not mean "cannot be kept." It is about order: wait until the tank has settled. Goldfish are covered in Goldfish Tank Mates.
What size tank should tropical fish beginners start with?
A tank 60 cm wide is an easy size for beginners. The more water there is, the less suddenly temperature and water quality change.
Tokyo Aqua Garden recommends a 60 cm tank for beginners. It says small tanks make it harder to keep the water in good condition.
Here is roughly how much water each tank size holds.
| Tank | Approximate water volume | What it suits |
|---|---|---|
| Small set about 25 cm wide | About 12 to 20 L | A few fish, such as one betta |
| 30 cm cube | About 24 L | Just a few small fish |
| 45 cm wide | About 42 L | One school of one small species |
| 60 cm wide | About 56 L | A school plus bottom dwellers |
| 90 cm wide | About 160 L | Also active swimmers such as zebra danios |
Seriously Fish recommends a roomier tank for neon tetras and rasboras, with a base of at least 60 cm wide × 30 cm deep. Kept in schools, the numbers add up fast.
If in doubt, choose a tank 60 cm wide, so a school and bottom dwellers can share it. The water alone weighs about 56 kg, so place it on a stand that can carry the weight.
What do tropical fish beginners need?
The basics are a tank, a filter, a heater, a thermometer, a light and a lid. You also need water conditioner and a water test.
| Equipment | What it is for | What to look for |
|---|---|---|
| Tank | Where the fish live | If in doubt, 60 cm wide |
| Filter | Removes debris and gives bacteria a place to live | Matches the tank size |
| Heater | Keeps tropical fish at their suitable temperature | The water volume printed on the box |
| Thermometer | Lets you notice temperature drift | A spot you can read at eye level |
| Light | For viewing fish and growing plants | Set fixed hours for it to be on |
| Lid | Stops fish jumping out and water evaporating | Few gaps |
| Water conditioner | Neutralizes chlorine in tap water | Use it at every water change |
| Water test | Measures ammonia and nitrite | Which items it can measure |
| Substrate | Looks, and a place to plant | Fine sand suits corydoras |
| Net and bucket | Moving fish and changing water | Keep them for the fish only |
Tap water contains leftover chlorine from disinfection. This is because Japan's Waterworks Act requires chlorine to remain in water at the tap.
What comes in a set depends on the product. Some sets sell the heater or substrate separately, so check the contents of the box.
The heater is easy to overlook inside the tank. Put the thermometer where you look every day, and you will also notice a failure sooner.
When you buy a set, first check that you have a heater, a thermometer and water conditioner.
How much does it cost to start keeping tropical fish?
Starting with a tank 60 cm wide costs about 10,000 to 40,000 yen for equipment and fish. Prices vary a lot by shop and season.
These are the price ranges for new items seen on a Japanese price comparison site in October 2026. Product names are left out, and items are grouped by type.
| Item | Price range | What makes the range |
|---|---|---|
| Tank set 60 cm wide | About 6,000 to 17,000 yen | Type of filter, whether a light is included |
| Heater (150 W) | About 1,000 to 7,000 yen | Fixed-temperature or adjustable |
| Water test (test strips and others) | About 500 to 3,000 yen | Number of items it measures |
| Thermometer, water conditioner, net, substrate | A few thousand yen in total | Amount and type of substrate |
| Fish | From about 1,000 yen per species | Species and number |
For fish prices, Tokyo Aqua Garden listed 10 neon tetras at about 1,000 yen. Five corydoras were about 1,100 yen.
Fixed-temperature heaters are cheaper, and adjustable ones cost more. An adjustable heater is the one you can set to suit the fish you keep.
How to set the temperature is covered in Tropical Fish Water Temperature.
The start-up cost can differ by a few thousand to about 10,000 yen, depending on two things: what the set includes and the type of heater.
What are the monthly costs of keeping tropical fish?
The monthly costs are electricity plus supplies such as food and water conditioner. Electricity depends on power use and how long each device runs.
You can work out the electricity cost like this.
- Divide the power (W) by 1,000 to get kW
- Multiply by the hours on per day and the number of days
- Multiply by the price of electricity
For the price, we use the guideline rate set by Japan's Home Electric Appliances Fair Trade Conference: 31 yen per kWh. Here is an example.
| Equipment | Example power | Example hours on per day | Electricity for 1 month (30 days) |
|---|---|---|---|
| Heater | 150 W | 6 hours | About 840 yen |
| Filter | 10 W | 24 hours | About 220 yen |
| Light | 15 W | 8 hours | About 110 yen |
| Total | About 1,170 yen |
A heater switches off once the water reaches the set temperature. In a cold room in winter it runs longer, and the bill goes up.
The power and hours in the table are examples for the calculation. Check the power rating of your own equipment on the unit or the box before you calculate.
How should tropical fish beginners plan the first month?
Cycle the tank before adding any fish. Move to the next stage based on water test results, not on the number of days.
| Stage | Rough timing | What to do | Sign to move on |
|---|---|---|---|
| Preparation | Day 1 | Place the tank, fill it, start the equipment | No leaks, and the temperature is steady |
| Cycling | About 2 to 6 weeks | Grow bacteria without fish | Ammonia and nitrite at 0 |
| First species | After cycling | Add a small number of one species | They eat, and the readings stay at 0 |
| Second species onward | After the first species | Add one species at a time | Test the water each time you add fish |
Cycling means growing bacteria that break down fish waste, in the filter and the substrate. Sources give a range of times for it.
The steps of cycling, and why the timing varies, are covered in How to Cycle a Fish Tank.
The timings are a guide. Move on when the water test says so, not the calendar.
Think of the first month as a time to "grow the water," not to add more fish, and you will make fewer mistakes.
How many fish should tropical fish beginners add at first?
Add just one species at first. If you add many fish at once, the bacteria, still growing, cannot break down all the waste.
Practical Fishkeeping recommends adding fish in stages. The more fish and food there are, the more ammonia there is.
Add schooling fish at their group size (see the table). Here is an example order.
| Order | Example | Reason |
|---|---|---|
| First species | Platy | Its group size is fairly small |
| Second species | Neon tetra or harlequin rasbora | Adds a school in the middle |
| Third species | Panda corydoras | Sensitive to poor water, so wait until the tank settles |
| Fourth species | Shrimp | After checking compatibility with the fish |
When you add fish, float the bag in the tank to match the temperature. Then add tank water to the bag little by little so they get used to it. For details, see Acclimation.
Choose two species to see their compatibility and the reason.
After adding fish, check that ammonia and nitrite stay at 0 before you add the next ones.
What daily and weekly care do tropical fish need?
Care centers on checking the temperature and feeding every day, and on water changes and water tests every week.
| How often | What to do | Guideline |
|---|---|---|
| Every day | Check the temperature | Inside the suitable range in the table |
| Once every 1 to 2 days | Feed | An amount eaten in about 3 minutes |
| Every week | Water change | 1/5 to 1/3 of the water |
| Every week | Water test | Ammonia at 0 |
| When the filter media clog | Clean the filter | Do not over-clean |
A University of Florida guide recommends testing for ammonia at least once a week. If the fish start acting differently, test right away.
Avoid changing all of the water. Tokyo Aqua Garden also advises against full water changes.
Fish act hungry every time. Decide the amount by how long they take to eat it, not by how they act.
Simply keeping each feeding to "what they eat in 3 minutes" greatly reduces dirty water.
What mistakes do tropical fish beginners often make?
The three common mistakes are adding all the fish at once, overfeeding and not checking compatibility.
| Common mistake | What happens | What to do instead |
|---|---|---|
| Adding all the fish on the day you buy the tank | Ammonia builds up | Cycle first, then add one species at a time |
| Overfeeding | Leftover food fouls the water | An amount eaten in 3 minutes |
| Changing all the water | Temperature and water quality change suddenly | 1/5 to 1/3 at a time |
| Washing the filter thoroughly | Bacteria are lost | Rinse lightly, only when it clogs |
| Going into winter without a heater | The water gets cold | Tropical fish need a heater |
| No lid | Some fish jump out | A lid with few gaps |
| Ignoring adult size | The tank gets cramped, and small fish get eaten | Choose by adult size |
| Not checking compatibility | Chasing and fin nipping | Check a compatibility chart |
Over-cleaning the filter is a mistake that is hard to notice. Practical Fishkeeping says over-cleaning reduces the bacteria.
Most mistakes come from going "too fast, too much," so when in doubt, choose less and slower.
What should tropical fish beginners do when a fish looks unwell?
First measure the temperature and the water. If ammonia or nitrite shows up, change part of the water and feed less.
A University of Florida guide describes what to do when ammonia appears.
- Stop or cut back feeding. For 1 to 3 days, there is usually no harm to fish other than fry
- In an aquarium, change 25 to 50% of the water
- Keep the water well oxygenated
Here is what to check first for each sign.
| Sign | Check first | What to do |
|---|---|---|
| Gasping at the surface | Ammonia, nitrite, oxygen | Change part of the water and stop feeding |
| Not eating | Temperature | Check the heater and thermometer |
| White spots on the body | Ich (white spot disease, which causes white spots) | Use an aquarium fish medicine as directed |
| One fish is being chased | Tank mate compatibility | Separate it into another tank or with a divider |
Ich often comes in with new fish. A University of Florida guide recommends watching new fish in a separate tank for at least 30 days. Treatment is covered in Ich (White Spot Disease).
Even when one fish is weak, putting the water right first is what also protects the other fish.
What terms come up when starting with tropical fish?
| Term | Meaning |
|---|---|
| Cycling | Growing bacteria in the filter and substrate before adding fish |
| Filter | A device that circulates water and removes debris. A home for bacteria |
| Water conditioner | A product that neutralizes chlorine in tap water |
| Ammonia | A substance from fish waste and leftover food that is toxic to fish |
| Nitrite | A substance made from ammonia. Also toxic to fish |
| Group size | The minimum number of companions a fish needs to live calmly |
| Bottom dwellers | Fish and shrimp that live on the bottom of the tank |
| Acclimation | Getting new fish used to the tank's temperature and water little by little |
What else should tropical fish beginners read?
Beginners have an easier start once they understand cycling and tank mate compatibility. Go on to whichever topic interests you.
- Steps and timing of cycling: How to Cycle a Fish Tank
- Compatibility for 23 species at once: Tropical Fish Tank Mates Chart
- A classic for the middle: Neon Tetra Tank Mates
- A classic for the bottom: Corydoras Tank Mates
Care basicsHow to Cycle a Fish Tank: How Long Filter Bacteria Take, the Steps, When to Add Fish, and Fixes for Cloudy Water or Weak FishHow to cycle a fish tank, explained through filter bacteria and the nitrogen cycle. Steps, timing, when and how many fish to add, testing, and fixes for cloudy water.
Tank-mate chartTropical Fish Tank Mates Chart: 23 Species Rated ○△× with Reasons, Safe Sets and MistakesCheck tropical fish tank mates in order: temperature, size, fins and temperament, then shrimp. A ○△× chart for 23 species with reasons, safe sets and mistakes.
Tank mates by speciesNeon Tetra Tank Mates: 22 Species Rated ○△× with Reasons, plus Medaka, Shrimp, CardinalsNeon tetra tank mates for 22 species, rated ○△× with reasons. Bettas, angelfish and goldfish are ×. Medaka, tiger barbs, shrimp and cardinals, with sources.
Tank mates by speciesCorydoras Tank Mates: 22 Species Rated ○△×, Shrimp, Crowded Bottoms and How Many to KeepCorydoras tank mates for 22 species, rated ○△× with reasons. Bettas, medaka and goldfish are ×. Shrimp, sharing the bottom with plecos, and how many to keep.What do beginners often ask about tropical fish?
What tropical fish are best for beginners?
Small, peaceful fish suit beginners, such as neon tetras, harlequin rasboras, platies and corydoras.
Combine species whose ranges overlap in the "temperature overlap" of the table.
What do you need to start keeping tropical fish?
The basics are a tank, a filter, a heater, a thermometer, a light and a lid. You also need water conditioner and a water test.
Check the box to see whether the set includes a heater.
How much does it cost to start keeping tropical fish?
With a tank 60 cm wide, about 10,000 to 40,000 yen for equipment and fish. Prices vary by shop and season.
You can calculate the monthly electricity cost from power use and running hours.
Can I put tropical fish in the tank on the day I buy them?
Yes, if the tank has finished cycling. Do not add them to a newly set-up tank until cycling is complete.
When you add them, match the temperature first, then let them get used to the water little by little.
Are small tanks better for beginners?
In a small tank, temperature and water quality change more easily. Sources recommend a tank 60 cm wide for beginners.
If you combine a school with bottom dwellers, a tank 60 cm wide is an easy size to manage.
Do tropical fish always need a heater?
Tropical fish do. It keeps the water at the suitable temperature in the table all year.
Medaka and goldfish need no heater, so keep them in a separate tank from tropical fish.
Sources
- Seriously Fish: Paracheirodon innesi (neon tetra. Most on sale are farmed and adapt more easily than wild fish, weakened by long farming, tank base, hardiness field is "unknown")
- Seriously Fish: Trigonostigma heteromorpha (harlequin rasbora. Recommended without hesitation to first-time keepers, tank base)
- Seriously Fish: Puntius titteya (cherry barb. Recommended to beginners without hesitation, peaceful)
- Seriously Fish: Xiphophorus maculatus (platy. Suits beginners in fairly hard water, does poorly in acidic soft water, weakness from farming)
- Seriously Fish: Poecilia reticulata (guppy. Shop fish are sometimes weak from inbreeding, breeds readily, keeping one sex)
- Seriously Fish: Corydoras panda (sensitive to poor water, keep the substrate clean)
- Seriously Fish: Danio rerio (zebra danio. Hardy and reasonably priced, tank base)
- Seriously Fish: Paracheirodon axelrodi (cardinal tetra. Wild-caught fish are sensitive to poor water)
- Seriously Fish: Otocinclus macrospilus (almost all wild-caught and sensitive to water quality, fewer problems in a settled, well-planted tank)
- Seriously Fish: Pterophyllum scalare (as it grows, the angelfish may eat small fish)
- Seriously Fish: Betta splendens (the betta is best kept alone)
- Seriously Fish: Puntigrus tetrazona (tiger barb fin nipping)
- Seriously Fish: Ancistrus cf. cirrhosus (bristlenose pleco territory)
- RSPCA Australia: How should I care for my goldfish? (goldfish care)
- UF/IFAS EDIS FA031: Ammonia in Aquatic Systems (food and ammonia, test at least once a week, stop feeding, change 25 to 50% of the water)
- UF/IFAS EDIS FA006: Ichthyophthirius multifiliis (White Spot) Infections in Fish (watch new fish for at least 30 days)
- UF/IFAS EDIS FA124: The Ornamental Fish Trade (preparing before adding fish, acclimation, overfeeding)
- Practical Fishkeeping: How to Cycle a Fish Tank (cycling time, add fish in stages)
- Practical Fishkeeping: Why won't this cloudy water clear? (over-cleaning the filter reduces bacteria)
- Tokyo Aqua Garden: How to keep tropical fish (熱帯魚の飼い方, in Japanese. Recommends a 60 cm tank, equipment, acclimation, amount of food, amount of water to change)
- Tokyo Aqua Garden: Tropical fish recommended for beginners (初心者におすすめの熱帯魚, in Japanese. Listed prices of neon tetras and corydoras)
- Tokyo Aqua Garden: Tank sets for beginners (初心者向けの水槽セット, in Japanese. Water volume by tank size, equipment often sold separately)
- Kanagawa Prefecture: Reducing and leveling residual chlorine concentration (残留塩素濃度の低減化及び平準化, in Japanese. The Waterworks Act requires chlorine to remain in tap water)
- Home Electric Appliances Fair Trade Conference: FAQ (よくある質問, in Japanese. Guideline electricity rate of 31 yen per kWh)
- Kakaku.com: Search results for aquarium sets (水槽セット, in Japanese. Price range of sets 60 cm wide seen in October 2026)
- Kakaku.com: Search results for 150 W aquarium heaters (水槽用ヒーター 150W, in Japanese. Price range and types seen in October 2026)
- Kakaku.com: Search results for water test strips (水質検査 試験紙 亜硝酸, in Japanese. Price range and items measured, seen in October 2026)
Read next
Care basicsTM-13How to Cycle a Fish Tank: How Long Filter Bacteria Take, the Steps, When to Add Fish, and Fixes for Cloudy Water or Weak FishHow to cycle a fish tank, explained through filter bacteria and the nitrogen cycle. Steps, timing, when and how many fish to add, testing, and fixes for cloudy water.Care basicsTM-14Tropical Fish Water Temperature: Chart for 23 Species, Setting It for Tank Mates, Heater Wattage, Summer Heat, Winter, Power Outages and How Goldfish and Medaka DifferTropical fish water temperature chart for 23 species. Setting it for tank mates, heater wattage by volume, thermometers, summer cooling, winter, outages and goldfish.Care basicsTM-15How to Acclimate Fish: Matching Temperature and Water, Drip and Cup Method Steps and Timing, and Notes for Shrimp, Medaka and GoldfishHow to acclimate fish, step by step with times for temperature and water. Drip vs cup method, why shrimp need longer, why bag water stays out, medaka and goldfish.