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A Beginner's Guide to Tropical Fish Identification

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A Beginner's Guide to Tropical Fish Identification

Whether you’re a beginner fishkeeper or you’ve been cultivating a tank for years, there are bound to be a few species of fish that you aren’t familiar with. There are thousands of different types of tropical fish that we know of, and probably a fair few that humans have never set eyes on.

So, identifying the species that you spotted and fell in love with, but forgot to find out the name for can be tricky! However, we’re here to help you learn what to check for so that next time you can hopefully figure out what you’re looking at.

If you’re searching for that beautiful fish that you don’t know the name of; or you just want to build on your knowledge of the aquatic world; this article is for you. Here, we’ve listed some of the more common families of tropical fish and explained what to look out for, so you can make an educated guess next time you’re trying to identify a friend with fins!

1. Cichlids

Examples: angel fish, koi angels, butterfly fish

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There are at least 1600 types of cichlids that we know of, and possibly many thousands more that we haven’t identified or even seen yet. They vary quite a lot in size, but in general, they tend to feature oval-shaped, quite flat bodies; and be of a medium size.

They also all share one main characteristic – a single tooth-bearing structure that is made from the fusion of the lower pharyngeal bones in the throat.

The koi angel is a type of angel fish that features mottled black and white colouring, occasionally also with gold markings on the fish’s head.

2. Pufferfish

Also known as blowfish

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The easiest way to identify a pufferfish is when it is feeling threatened, as it will inflate to several times their usual size – though, of course, we don’t recommend that you start threatening any fish! Apart from this rather impressive party trick, though, they also have large eyes, rough skin, long bodies and a beak-like mouth which features four teeth.

3. Cyprinids

Also known as the minnow or carp family; examples include barbs and danios

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This family of fish is incredibly varied, but perhaps the most interesting and noticeable characteristic that all its members share is a complete lack of teeth in their jaws. These fish instead use pharyngeal teeth, which are in their throats. Cyprinids also don’t have stomachs.

There are many different types of fish that make up the cyprinid family. One type that is commonly found in aquariums is the barb. Barbs often feature barbels around their mouth – these are whiskerlike sensory organs, and are responsible for the barb’s name.

4. Characins

Examples: silver dollars, tetras

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There are thousands of species of characins, but one characteristic that they all share is an adipose fin, which is small, and is positioned behind the dorsal fin, and just before the tail or caudal fin. Characins also do not feature barbels around their mouths.

Apart from the characteristics mentioned above, characins can look quite a lot like cyprinids, so those are the things you need to look out for to distinguish between the two types.

Silver dollars are so named due to their disc-shaped body, which makes them resemble a coin.

5. Catfish

The plec is also in this family

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Like characins, catfish feature an adipose fin, but usually the easiest way to identify a catfish is by their barbells, which look like a cat’s whiskers, and which gave the fish its name. However, not all catfish have particularly prominent ‘whiskers’.

Another way to identify catfish is that they are bottom feeders, so will generally be found towards the bottom of the tank they’re in – some will also enjoy eating algae from the walls of the tank. Many types also have flattened heads; and catfish also have no scales, though some types have bony plates on their body which look like armour.

6. Anabantoids

Also known as the labyrinth fish; examples include the gourami and Siamese fighting fish

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This family of fish is unusual in that its members can breathe oxygen from the air, rather than through water as most fish do – in fact, as long as the fish is kept moist, it can even survive out of water for several hours. This ability is thanks to its complex, lung-like organ, which is known as the labyrinth organ. They tend to be of a medium size.

7. Scats

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These fish are scavengers, and feed on algae and faeces – hence their name, from the Greek ‘skatos’ which means faeces. However, despite having a reputation for happily eating what others wouldn’t, they aren’t necessarily too easy to look after, and may require an expert level of care, particularly as they age.

Scats generally reach around 25cm in size, and can reach 30cm, so they will need a large tank to accommodate them. Their bodies are generally quite flat and almost square in shape. Despite their taste for rather unsavoury foods, scats will be perfectly healthy when fed with more regular fish food, and will also keep algae levels down in your tank, which can be useful.

8. Botiidae

Example: botia, clown loach

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There are a few characteristics that can help with identifying these fish. These bottom feeders feature an arched, high back and a flat belly, as well as a pointed snout. Most types vary between six and 30cm in size, though some can reach up to half a metre.

A popular type of Botidae is the clown loach, which features three distinctive triangular black stripes along its body. The colour of the rest of its body can range from a white-orange to a more red-orange. It also features four pairs of barbels, and has a downward facing mouth.

Occasionally, the clown loach will use its pharyngeal teeth to make clicking sounds, especially if it is feeling territorial or mating.

Top tip

One of the best aspects of tropical fishkeeping is that there is a multitude of species to choose from; but this can also pose something of a problem when it comes to knowing which types can live in harmony together, and which might fight like cat(fish) and dog(fish).

Before you decide on which fish will populate your tank, it’s essential that you do your research to ensure that your fish will all be happy living together. You’ll also need to check what size of tank your fish will need, and what sort of water conditions and food they will require. If you need any help or advice at any point, please feel free to give our team a call.


This is just a starting point for identifying tropical fish – to cover each and every species would mean that you would be reading for a very long time – but hopefully this has offered you some useful information to get started on figuring out the differences between some of the more popular species of tropical fish.

Thankfully, we have plenty of experts on hand in house, so if you happen to get stuck at any point when you’re trying to identify a fish, please do get in touch and we’ll do all we can to help – we love a challenge!

Do you have any tips for identifying tropical fish? Let us know in the comments!

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