Suggestions on an algae eater?

[Bottomfeeder]

A 75 still wont be nearly big enough, especially given the potential size of the clown knife and the channel cat. Do you know how large they can get? Particularly the channel. Not to diminish the size of the clown knife, but the channel cat will be far too big for a 75g before you even blink.

 

[Redearsunfish]

Don't depend on fish to keep algae at bay, depend on this:

1. water changes.
2. responsible feeding (don't over feed)
3. Only use tank lights when viewing your fish. (i.e., tanks only need ambient room light when not being viewed)
4. Keep tanks away from windows, or natural sources of sunlight.
5. Use a algae magnet.
6. If all else fails, invest in a UV filter.