Cory & Otocinclus - What's the difference?

otos eat algae
cories eat almost anything on the bottom

same size pretty much

otos tend to be hyper
cories more laid back

otos (I'm told) are very sensitive and can even starve in a tank with feeding
cories are more tolerant, but not as tolerant as a danio


If you don't have a lot of algae (and you probably don't in a cycling tank) don't add otos. Get cories, they are neat, fun fish. Later, if you start to have an issue with algae, then add otos.

Keep in mind that both are schooling fish (like danios) and more is better, but with otos, more won't have enough to eat in a 10g tank.

Three otos have pretty much cleaned my 55 in a week.

You can do 2-4 ottos in a 10G. The keys are to make sure you get big healthy ones to start with, and get them to recognize algae wafers as food asap. I've found that the Wardley's brand is much more readily accepted by ottos than brands like Hikari which is the favorite of my BN's/Cories.

Cories won't clean algae in your tank, so you'll want to make sure to watch your lighting or expect to do a decent amount of scrubbing.

Cories tend to school together when you have 3-4 or more of them. Otos occasionally will hang out together, but for the most part will each be off munching on algae in different places. When it comes to hardiness, it really depends on which cories you are thinking of getting, and also a degree of luck with the otos. Some cories such as pandas are really sensitive to water conditions.

What else are you going to have in the tank? In either case I would recommend you consider adding some driftwood and live plants (hygro polysperma, bacopa, sagittaria, java fern and foxtail all come to mind for a low-light 10-gallon. The otos will love to rasp onto them, and it will provide much more surface for them to graze on. Also, most fish will enjoy the added security of having some plant cover.

Depending on what other fish you are planning to add, I would recommend no more than 2 otos, or 3 small cories. I would also wait until later to add the catfish if you are plannin on adding other fish.. cories and otos will not do well in a cycling tank. Oh ya.. as for size, the otos are smaller on average than most cories (except for pygmy, panda and other small cories). The otos will get up to about 1.5-2'' max.. some cories such as bronze and skunk cories can can get up closer to 3''.

Goodluck!