Wrong ID....Maybe...

[GhostArcher]

So back in Oct 2012 I got these fish. I originally thought that they were

Ancistrus cf. cirrhosus

and several others confirmed my ID. They were being sold as

Hypostomus plecostomus

which I knew 100% that they are not. Now, here is my problem. They were bought at roughly the same size as my albinos and in 6 months my albinos had grown a ton and were breeding. These fish on the other hand have not grown at all. They are literally the same size I bought them at (about 2.5" - 3"). They are kept in the Exact Same water conditions as the albinos, same feeding schedule, same water change schedule, same lighting schedule. What the hell is going on with these fish or, did I simply misidentify them? If I did get the ID wrong please help me out and tell me what species they are.

[MatsP]

Looks like

Ancistrus cf_cirrhosus

to me. Also looks like all females, which may explain why they are not breeding... ;)

--
mats

[GhostArcher]

Looks like

Ancistrus cf_cirrhosus

to me. Also looks like all females, which may explain why they are not breeding... ;)

--
mats

cool thanks. I just don't understand why they are not growing.

[Richard B]

Growth of a species, to near it's maximum expected size depends on a number of things, some of which i'll crudely discuss below.

Food - bristlenoses like a lot of plecos are really 'constant grazers' & do well when they have access to food all the time. In practice, for me anyway, i cover this by having vegetable matter in the tank all the time. A weighted lettuce leaf or blanched green beans might have to be changed in a couple of days but a slice of sweet potato might last a week. There are so many fruits & veggies that can be used so its easy to provide something all the time.

Water - constant grazing equals contant waste production so water quality must be considered & quality maintained by correct filtration, aeration, & water change regime.

Genetics - some fish have been so line bred/inbred that sizes diminish after a while. With common bristlenose it's sometimes hard to say what the heritage is.

Space - it is well documented that some fish can become stunted in tanks that are too small but i dont think this applies to BNs.

As an experiment could you swap your BN's over from one tank to the other & vice versa to see if the browns then start to grow?