Surgeonfish in marine aquariums: how many and why?

Surgeonfish in marine aquariums: how many and why?
Acanthurus leucosternon

I’ve always loved aquariums full of fish, as if you were diving in tropical seas. I’ve always had a lot of them, the important thing is knowing which one you can insert and respecting them, obviously.

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This article is also available in: italiano

At the end, it’s all an exercise of equilibrium and proportions. A big fish in a small aquarium it’s not that nice to see and it’ll also make your aquarium appear even smaller than it is, wherever the beauty of the fish. Moreover, a lot of fish that don’t fit for their size, for example some surgeonfish, become very aggressive and can attack other fish, they can get sick frequently, infecting then the other specimens too. Then you have to consider the biological niches, for which it would be totally useless, for example, insert 20 angelfish and then complain that the noone swims in the upper part of the aquarium. Then you have to consider the colors, because some fish get very aggressive towards specimens with similar liveries. And shoal fish have to stay in shoal… and so on. But let’s continue with order.

Is there a maximum number of fish that can be kept in a marine aquarium? No, there isn’t. If you wat to obtain the maximum from your aquarium, you have to study, know and respect the fish. Choose them wisely.


Let’s start from the classic ones: surgeonfishes. This fish are very beautuful, tireless swimmers and great seaweed eaters. They’re quite big and need their space for swimming, so they prefer rectangular rather than square aquariums. They don’t like to be more than one in the same aquarium because of the small space they can get. So the limit in this case is simple, if you have less then 300 liters avoid every surgeonfish. It will be better both for the fish and your tank, and smaller fish will make your space looks more balanced.

Let’s say that, generally, the Zebrasoma can adapt in a space between 300 and 400 liters. The Ctenochaetus already need 400 liters for a start. The Acanthurus will need 500 liters as well as the naso, but if your tank is rectangular and you don’t have many animals maybe it will fit even 400 liters. In any case you have to study animal by animal. A Sohal, for example, although it’s an acanturidae should never stay in an aquarium with less then 750 liters.

Consider even that surgeonfish need to eat seaweeds, a lot of seaweed, from the nori that you buy at the supermarket to those packaged for aquarium fish, but also plant-based granular food. And very proteic food for sustaining their swimming.

Here below there are two articles we made about surgeonfish, but they’re in italian

so, you’re very welcomed to ask any question you need and we’ll be glad to help you, here in the comments or in our forum.

From the same series:

We’re currently writing some articles on the various families of fish, and we we’re going to collect below each article the links of the same series. And is there a particular family that you’d like to learn more about?

  • Surgeonfish in marine aquariums: how many and why?
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