Good Fish for a Small Reef Tank

For one reason or another, my site has been getting some hits from people searching for “Good Fish for a Small Reef Tank”, even though I’m not sure I’ve ever posted anything on the subject.  With that in mind, I thought that I might as well write up a little article documenting what I’ve learned in the past couple years setting up my tanks.  Please keep in mind that most of what I have learned comes from reading a bunch of garbage online, and eventually screwing things up before learning how to fix my mistakes.  Another thing to note is that this info is only applicable for a reef tank.  I’m not personally a fan of FoWLR tanks (fish only with live rock) so I’m not the best source of information for that sort of setup.

What type of fish you put in your tank depends on a number of things, but first and foremost on what you WANT to put in your tank.  If you’re going to have a reef tank (which I would certainly recommend on nothing more than personal preference) then make sure that whatever fish you put in your tank is reef compatible, meaning that the fish won’t destroy your corals.

Another important thing to factor in is the size of your tank.  Are you running a 10 gallon tank you got from your local pet store?  Do you have a new BioCube?  Maybe you’ve got a 20 gallon long.  “Small” means different things for different people, but be aware that the smaller the tank, the fewer fish you’ll want to have.

A lot of people go on youtube and see beautiful videos of the smaller BioCube aquariums that have got 5-10 smaller fish in them and are packed with coral.  While these are amazing to look at, I can promise you that those tanks don’t survive without a fair amount of human intervention (either by dosing, filtration, or massive amounts of water changes to keep all the nitrates down).  Over stocking your tank will result in unhappy fish, high nitrite/nitrate/ammonia levels, and generally a lot more work for you.  I’m not going to tell you what to do.  Maybe that all sounds like fun to you.  To me however, I’d rather have a tank that I can enjoy without having to work on every day just to keep things alive.  It also makes it a lot easier if I want to go on vacation and need to have one of my friends come over and feed my fish.

I know that I still haven’t given you a straight answer yet, but it’s important that you know the factors that go into what I believe is a good reef tank before I can give you any sort of recommendations.

There are so many good fish for small tanks.  While I’m not going to list them all, my rule of thumb is if you’ve got a 10 gallon tank, I wouldn’t go with more than one fish that could potentially grow to be more than 2.5″ in size.  One important thing to note is that there are a lot of wonderful fish that fall into this category that are school fish or fish that like to pair off. Personally I would avoid these.  They will probably do just fine, however I hate the thought of taking a fish that would much rather live in a pair or a school and sticking them in a tank alone.  There are plenty of fish that generally hate being around anything else alive that would love to live in your small tank all alone.

If you have a 20 gallon tank, then I’d consider going up to something that pairs as there are few things more amusing to watch than a pair of fish interacting with each other. I know everyone has them, but clown fish are wonderful fish (even for first timers).  They are beautiful, they have a TON of personality, and they are very robust (being damsel fish).  There are also more varieties than I care to name so you can get them in almost any shape/size/color combination.

As you go up in size, you can go up in fish count.  If you add a sump/refugium you can again increase in fish count or size.  I prefer to have an understocked tank so that everyone has room to swim around and so that I don’t have to deal with as much maintenance as if I had an overstocked tank.  At the end of the day however it’s your tank and you can do with it as you please.  Just be nice to your fish and don’t put them into an environment where they will be unhealthy or unhappy.

I will try to post more articles as I go on, if for no other reason, to document the stuff I’ve learned by screwing things up.

For more info, click on the “Reef Tank Info” tag below.