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Otocinclus Catfish

4957 Views 17 Replies 4 Participants Last post by  AltheaGlyndwr
I've read many differing viewpoints on care for these little guys. I recently (just over 2 days ago) aquired an oto and would like to know how people have helped theirs thrive. In my tank I already had 6 Ghost Shrimp, a marimo moss ball, an Endoa plant, a Lucky Bamboo, a filter, heater, a light, and several caves/hidey places with marble pebble terrain. The tank has cycled since becoming established on the 12th of May after I lost my betta and cleaned everything out.

What are special needs I need to be aware of? I already have algae growing in my tank as well as some algae wafers. How often should I actually feed her? (I'm pretty sure its a girl) Also, how long will she take to fully adjust and perk up to be her normal self? At first she went crazy swimming around the tank on the substrate cleaning the algae off of the few rocks I have in there but she has since slowed down and is just kinda chilling in one area of the tank. At one point I actually thought she was dead but then when I moved my hand near her she totally moved. Is there anything that I can do to make her more comfortable while fully adjusting and make sure that she will survive? I've read they're hard to keep unless it's perfect. I also haven't named her yet because I'm scared of losing her (the last time I lost both my betta and the two ADFs within 2 days) and I don't want to do anything wrong.

Also, I know it's not very big, but I'm using a 5 gal cause that's all I have room for until I eventually move and I had been able to upgrade from the terrible .7 I had been using for my poor betta without realizing it was far too small. (When I do finally get the courage and space to get another betta it will only touch that tank if it gets sick as a hosp tank.) I've already learned so much from the community here and I'd really like to make sure I do the best I can with these guys.
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TFK ( is the parent site for; your login will also work there. They have detailed profiles for a lot of tropical fish including oto catfish. You can read it here: Oto Catfish (Otocinclus macrospilus) Profile

From what I've heard about oto catfish, they need a mature tank. The cycle is the just the really tumultuous part of a tank establishing itself. Maturation of a tank happens in the next 3 - 4 months. This is when the biology of the tank is stabilizing; the parameters become pretty set, and the ecological community (algae, bacteria, and other microinverts) become well established.

They are also a schooling fish and do need groups; they also do best in heavily planted tanks. I've also heard they are very very skittish and they poop a LOT. I've considered them for my 29 gal softwater community, but I'm waiting to see how the algae developes. They do need a good supply of algae in the beginning. They are true algae eaters, and all specimens are wild-caught. The tanks they are housed in typically don't have enough algae to sustain them and they arrive in the store half-starved. Once they eat their fill of the algae in your tank, they can be transitioned to algae wafers.
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Try to get large-leafed plants like anubias and java fern. Otos really like them. You can also try to entice him with green veggies like zucchini. Those little guys are sensitive little buggers. Best of luck keeping them alive.
If the java fern is the "tropical fern" that comes in a tube, you don't have to QT it. Just give it a good rinse off in tap water before you put it in the tank. They might also have anubias in the tubes; my petsmart does. Those are another good choice for your tank. The best way to ID these plants is by the scientific name: anubias (Anubias barteri) and java fern (Microsorum pteropus).
That is different from the setup my Petsmart has. Since the plants are in contact with water that other fish have most likely been in, I would QT them for about a week. No fish disease can survive that long without a host and will also give you time to pick out any snails that may come with the plant. Be sure to throw away the water the plant comes in because it may be harbouring some diseases. Get some water from your tank, put the plant in that, and set the QT tank by a window. It wouldn't hurt to change the water on your QT tank with water from your main tank once or twice as it will give your plant some more nutrients to stay strong and keep growing.
I'm sorry you lost some more. Otos are not an easy fish to keep alive. All are wild-caught and usually come to the store in very poor condition. If you can get your tank well-planted and let it age for a while, maybe you can try otos again.
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