Big fat Otocinclus

Probably pregnant. Right before my female layed eggs she was HUGE! Oto's bellies should be almost this big normally, the problem is we are used to seeing them in the LFS with skinny tummies, poor babies.

3 of my 4 look like yours. I have tons of algae for them to eat. All mine do for the most part is eat and hang out stuck on my spraybar.

Generally as they get older (and fatter) they get less active. My LFS told me that the younger ones are more active and eat more.

I would say not sick or pregnant. Maybe it's a female (they are larger) and they eat a lot. I have two of them. One looks fat, the other skinny. Both live in the same tank, both eat a lot. I've concluded that I have a female and male in the tank and that's why they look different. Males are usually smaller. Both have round tummy's but the females is a lot larger. I don't think it's pregnant, just full.

My oldest Oto now back in the main tank... is getting seriously huge. She looks like she's about to blowup. I've been wondering if it's a problem, there's no way she can rest her belly on a flat surface. But she's a total piggy. Not only does she devour the sides and plants, she devours the algae wafers - and eats flakes every day with gusto.

Might she eat herself to death...??

Thats just a well fed oto. Most of mine look like that. I always think they could be pregnant but thats very unlikely.

Cool, I was just about to ask how to sex them and you guys already gave me what I need. I think I have 2 males and 3 females. A pair of them always swims together throughout the 110.