I imagine that the petricola would eat molly fry, although these catfish are still very small. These mollies have dropped scores of fry since I got them, most of which have been eaten be the mollies and other tankmates. I was so gung-ho about my livebearers that I got down in Mexico, but haven't spent much time lately working with them because I have been so busy with other things. Getting these fish into this tank and getting better looks at them has renewed my interest in building up their colonies again. I have several different species of goodeid and poecilid livebearers that I collected down there during a couple of trips. Did you ever see the one trip journal that I put together? It is right here.
One of my friends neighbors breeds Ancistrus type plecos. One of the strange things he's told me is that he keeps petricolas with his plecos and the petricolas will hold the babies in the mouth. Which i thought to be funny but apparently if you search hard enough on the web you can find similar stories.
The websites describing this fish state that it needs hard, somewhat alkaline water. Is that correct, or are they like so many fish in that they will adapt to what ever water you have if you acclimate them to it? My tap water is very soft.
I understand that they are pretty adaptable. I think that the breeder who sold this group to me said she was keeping them in moderately hard water with pH 7.6. This is not so hard like Lake Tanganyika water is. They probably wouldn't be suitable for very soft water with low pH.
If you keep this up I may be unable to avoid the temptation to get some of them Tell me their bad habits, quick!!!
A shoal of Pimelodus pictus could also be great for a species catfish display, and those are often readily available at the LFS. A couple of people suggested dwarf pike cichlids (Crenicichla sp.) as engaging possibilities for this setup while I was looking for ideas. Congos or another West African tetra could also be good and would probably appreciate the overhanging vegetation. Invertzfactory.com has those weird little gobies that could be neat additions. There are just a zillion different fish possibilities.