I agree, golden Chinese algae eater. They get to a decent size, my one got around 12cms but I've heard they can get bigger. They can be aggressive, mine used to chase my angels around and was always fighting with a red tail shark, I guess this was because they have a similar body shape so not sure 2 of them could live together without brawling.They like to munch on a bit of zucchini if you drop a slice in once in a while. My one jumped out one day and that was the end of him so keep the lid nice and tight. You used to see dyed ones for sale a lot with half blue or pink bodies but thankfully they aren't around anymore.