Hi Kim,
I don't think that it was that thin, the last time I saw it on the front glass it had a nice rounded belly (3-4 days before it died). What ever it had seems to of eaten the gut area away (it had gone through the skinand had a large hole in its stomach), it looked horrible. I have been feeding them flake food (which they deffinatly ate), bloodworms, brine shrimp, peas and zucchini. The only other fish in the tank was a smaller male Black Eyed Yellow Bristlenose. The two of them just left each other alone. I'm did not feed them meat (am I supposed to?). The only decorations in the tank was the wood and it had already been in there before the Black Eyes (the tank had regular Bristlenoses in there first). I think theat the pH was about 6.5.
I hope this helps.
Cheers, CatBrat.