Can I safely add some shrimp?

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Neale Monks offers his advice to a reader who is thinking about adding some Cherry shrimp to his aquarium set-up...

Q) I have a 90cm aquarium filled with small community fish. I have 12 Endlers, six Harlequins and eight Cardinal tetras. There are also four Bronze corys at the bottom. Could I add some Cherry shrimp to this set-up? If so, how many would be best?

JULES, VIA EMAIL

A) NEALE MONKS SAYS: Mixing small community fish, such as Cardinals, with small shrimp species, like Cherry shrimp, can work up to a point if there are plenty of hiding places. The male Cherry shrimp are much smaller than the females, so tend to be rather shy when kept with active fi sh species, but the larger females are rather more outgoing provided they’re not actively harassed. So, in this sense, yes, mixing shrimps and small tetras might work.

On the other hand, shrimp are best maintained as colonies rather than groups. Individuals tend to live for around 6-12 months at tropical temperatures (although they live considerably longer at subtropical temperatures), depending on how old they are when you purchase them. Even under ideal conditions, their life expectancy from hatching is not going to be much above two years. Now, this doesn’t matter if you purchase a decent sized group of males and females: once settled, they’ll breed rapidly, and you’ll soon have a thriving colony of adults and juveniles. As you probably know, the females carry the eggs about, and once the eggs hatch, miniature shrimp emerge that are perfectly capable of surviving in a mature aquarium — provided they’re not eaten. So far as a starting population goes, I’d suggest a dozen or more, with a mix of males and females if you want them to breed.

Unfortunately, pretty much any active predator fish, even one as small as a tetra, is going to view hatchling shrimps as food.

Your best bet might be to opt for larger shrimp species, such as Amano shrimp, even though these won’t breed under aquarium conditions. If you did opt for Cherry shrimp, there’s a good chance they’d end up temporary additions, lasting for only so long as the females survive, the males and juveniles having a much lower chance of doing well.

PLAY IT SAFE...

While many robust community fish such as tetras and rasboras will probably take baby shrimp given half a chance, there are some that pose no threat at all, such as Whiptail catfish and ricefish. The ricefish are surface feeders that ignore even their own fry, and Whiptails are strictly sand-sifters with a taste for worms.