Distinguishing Fish Type

[PrairieSunflower]

I'm curious, how can we tell fish apart and from what group they come from? I mean, when I'm in a shop and if I ignore labels... I can't tell a variety of tetra from a rasbora, for example. So, what qualities set fish apart? Livebearers are obvious since they have live babies rather than eggs... but what says "this is a tetra" and that one isn't?

 

[elmo666]

Good question, and I think the answer is that there isn't an easy way of telling, it's genetic. A cherry barbs shape is very similar to that of a neon tetra for example. Am sure someone with more knowledge than myself will explain thay there are similarities in physical traits, most tetra have a similar look, but there are stil cross-overs in shape and behaviour.

 

[Wills]

Barbs and tetras are easy IMO - most Barbs have really clear visible scales where as Tetras are generally smoother and have a flatter look to their sides. But there are exceptions - Galaxy Rasboras have tiny scales that are hard to spot and then Buenos Aires Tetras have quite large scales.

Loaches are pretty easy to spot with their slender shapes. Catfish is a bit of a minefield with species as some look very similar but totally different - eg Mystus Catfish and Pictus Catfish (not the main common species but some of the less common ones) But they are actually very different and from different continents.

Best thing to do is to learn your fish before you go to a shop - imagine walking into a large chain store and knowing all their fish without looking at labels. Well worth it learning as it can save some mega issues!

Wills

 

[PrairieSunflower]

No plans to add anything new to my tank, just trying to figure out differences. One day I want angelfish, but I don't have any suitable tanks... or places to put any more anyway!

 

[fluttermoth]

It can be difficult; fish vary so much that any 'diagnostic' feature may not be present in all species in that family.

For example, most tetras have an adipose fin (a small, 'false' fin, just in front of the tail), but it's absent in the silvertip.

Even 'tetras' themselves are no longer considered a good genus, as they've been found to be not as closely related to each other as previously thought.

There's really no reliable way of identifying fish just by looking, although you can make some informed guesses. Most people can easily learn to recognise Rift Valley cichlids, but identifying the actual species can be very difficult and sometimes involves techniques that we can't do as hobbyist, really, like counting pharyngeal teeth.


The only real, reliable way, is to find out the actual, scientific name of the fish and look it up!

 

[DrRob]

As Wills said, there are many trends that allow easy identification, but the most important thing about a fishes eventual shape is the niche that it's occupying, leading to some pretty big differences, but the telltale will generally be there, in some form or another, that allows you to tell what group the fish is in.

Otherwise, as said, research them first. Get an idea what you like from the pictures and descriptions, head to the lfs and write down the names of what you like and look them up afterwards, and hang around on forums and look up the fish that you like the look/sound of and realise that you really, really, need 20 more tanks.

 

[CezzaXV]

Even biologists aren't sure!

What is now sold as the Celestial Pearl Danio was once called the Galaxy Rasbora!