Is it ethical to keep only one green chromis?

jgranata13

New member
I know this is the umpteenth post about green chromis, so I'll try to keep it short. I have a 37gal tank with two ocellaris clowns, a fire shrimp, and some hermits and snails. I absolutely love chromis viridis more than anything - they're basically the reason I started with saltwater in the first place - but I'm not willing to try a school because my tank isn't optimal and I think it's irresponsible to "try and see what happens" when I'm pretty sure of the outcome anyways. I've read everything I can find online about their schooling behaviour and I really can't figure out if they get stressed out when kept alone. Some sources say they "shoal" rather than "school", and then claim this means that they do stay together in the wild but that it's not actually necessary. Others say they're "fine" on their own in aquaria (I'm not very fond of the word "fine" TBH), and others still say that they'll be stressed in anything less than a school of 7.

If anyone knows anything that I don't/has an opinion on whether or not it's ethical to keep only one, please share. My absolute dream is to have a school of 12, but in the meantime I'd love to have even just one; but only if the consensus is that it's not unethical to do so.
 
They don't school. They will loosely shoal, but they seem to usually whittle themselves down to only one chromis. Some people have had success keeping groups long term. They will dedinetly be fine on their own. When I had mine, it was pretty much ok with every other creature I put in the tank. But yeah, having one is definetly okay.
 
Yeah, I've read a lot about how their shoals are always very loose in aquaria, what I was referring to (though I guess I didn't explicitly say it) was their behaviour in the wild. I know it's very common for them to pick each other off one by one in aquaria, but this can't be normal in the wild, so I'm wondering if there would ever be an instance where they would naturally be alone (in the wild).

I guess ultimately what I'm trying to decide is, even though the dominant one may prefer to be alone in a tank rather than have others in a group, is that still the optimal way to house one if they would never choose to live alone in the wild?
 
The reason they school in the wild is because of a common predator, not because they like each other. More numbers = better chance of survival. Schooling is a defense mechanism, and unless you have a large predator in your tank such as a shark, they aren't going to school.
 
The reason they school in the wild is because of a common predator, not because they like each other. More numbers = better chance of survival. Schooling is a defense mechanism, and unless you have a large predator in your tank such as a shark, they aren't going to school.

Exactly!

BTW, the reasons they knock each other off, IMO, is partly because they are aggressive within their own species and partly because they need to be fed like anthias. I have a pair in my tank and they basically ignore each other; beyond one occasionally giving the other the 'fin'.

Not unethical to keep a single fish - do it with lots of different species. I only have one dog too.
 
So basically you're both saying that if the threat of predators is removed then their instinct to school for survival wouldn't kick in? Can they tell that there's no threat of predators if they're in a tank?
 
Yes they can tell. If you knew a murder or serial killer was in your house, you won't go in the house. Fish have brains and common sense to, trust and believe they know.
 
Thanks guys for your input! I'm satisfied now that I won't be causing undue stress by keeping only one. I have a red velvet fairy wrasse coming in today so I'll pick up a chromis at the same time. Cheers!
 
In case you needed further confirmation...I've had a single blue reef chromis in my 90 gal for about a year. No issues at all.
 
Fwiw my 5 greens and 4 bicolors get along with no issues. While the bicolor did split themselves throughout the rocks in the tank, the greens school with the anthias. I'm pretty sure the princess damsel that occasionally divebombs the chromis and all the big tangs, angels, and triggers helps as well.
 
Thanks guys for your input! I'm satisfied now that I won't be causing undue stress by keeping only one. I have a red velvet fairy wrasse coming in today so I'll pick up a chromis at the same time. Cheers!

Most fairy wrasses are too big for a 37g and really need a tank twice that size. He is going to have very little swimming room when he is full grown. And green chromis have a very high occurrence of a certain disease. I would advise quarantining the chromis alone.
 
The reason they school in the wild is because of a common predator, not because they like each other. More numbers = better chance of survival. Schooling is a defense mechanism, and unless you have a large predator in your tank such as a shark, they aren't going to school.

This.
 
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