# 21 gallon tank tank mates



## grantr222 (Feb 27, 2014)

Hi I have a 21 gallon tank that currently has a red tail shark, 6 neon tetra, 2 hatchet fish and an aquatic frog. Was wondering what I could add for some colour and excitement?? I was thinking maybe some gourami and rams?? I don't like guppys or Molly's. I have also attached a photo of my tank just for reference. Thanks in advance !


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## Phoenix24 (Apr 6, 2013)

Someone else might say more on this - but i'm not sure fish and frogs should be mixed?

What other fish you can have depends on the pH and hardness of your water, and the temperament of the fish that you have. The sharks tend to be quite aggressive and active fish, which wouldn't suit either gouramis or rams. That said, your tank isn't even big enough for a red tailed shark, which can grow quite large and need A LOT of space - particularly length (120cm minimum). So for a starters the shark (and maybe the frog) will have to go (somewhere other than in that tank).

You could try some harlequins, which are large enough and fast enough to hold there own, without being aggressive themselves. They are interesting shoaling fish that frequently display to each other, and you can tell the sexes apart.

Or some larger tetra species, such as the rosy tetra (again, shoaling, frequent displays, sexual dimorphism), the emperor tetra, silver dollars, and such like. Just don't go for aggressive, fin nipping types.

You could go for some of the more peaceful barb species, such as the cherries, or even the golden barb if the tank is not too hot.


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## NaomiM (Sep 22, 2012)

Some more hatchet fish - they're shoaling fish and should be kept in groups of at least 4 

I'd agree with most of what phoenix said, though I wouldn't recommendsilver dollars as your tank is a bit small for them - they can grow to about 6" and you need at least 3 of them.

Re the frog, what type is it - African dwarf frog or African clawed frog? ACFs are predators and should not be kept with fish as they will grab and eat even quite large fish! ADFs can sometimes be kept successfully with fish, but the main issue is making sure they get enough to eat, as the fish tend to snatch it all before they get the chance!

Have a look at AqAdvisor - Intelligent Freshwater Tropical Fish Aquarium Stocking Calculator and Aquarium Tank/Filter Advisor and try entering your existing stock, then having a play with some of the other ideas mentioned. It will give you an idea of how many fish you can comfortably fit in your tank, and will flag up potential issues such as tankmate compatability or fish that will outgrow your tank - though it doesn't catch everything, so it's best to do as much research as you can into a species before you buy!


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## Phoenix24 (Apr 6, 2013)

When I was in university there was a 3ft long aquarium right by my desk (which provided hours of useful procrastination!) in which there were hatchets, harlequins, several catfish, a pleco (which was too big for the tank) an angelfish (tank too shallow) plus a blue gourami that used to drive the angel mad by following it around.

The point being, you have to select fish based on the tank you have, or else buy a tank appropriate for the kind of fish you really want. It's no good throwing fish in together without doing the research first, you will only end up with sick/injured/dead fish and a hole in your pocket. I learnt that lesson the hard way, many times over, and still my set up is not 100% ideal. From your previous posts I can see you are not going to let the shark go, but my advice would be, long term, to consider investing in a tank that will suit the shark better.

As for tank mates, the following link has species accounts that include minimum tank sizes, water chemistry and temperature ranges, plus behaviour and compatibility.

Seriously Fish - Feeling fishy?

and here is the article on red tailed shark:

Epalzeorhynchos bicolor (Red-Tailed Black Shark) - Seriously Fish


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## grantr222 (Feb 27, 2014)

Thanks for the advice guys, I'm not sure what type of frog it is it was just labelled aquatic frog in the shop. He's very small though not even he size of your fingernail. With regards to the shark I am going to sell him I don't want him to be unhappy in there! I'll test my parameters and see what they are in regards to what fish to put in there thanks guys !


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