[Clean up crew for 55 gallon mbuna tank]

I have siphons. I was actually wanting to keep the glass specially cleaner. Typically I'd fight the algae with either less light/fertilizer, more plants and some nerite snails. But since cichlids are hard on plants  and they seem to want to kill snails none of those are really an option.  

[Clean up crew for 55 gallon mbuna tank]

I've been looking into getting some fish to help me keep my 55 gallon mbuna tank clean. I've heard plecos could be good, but I know the common ones get very large. 

I have 15 cichlids in the tank all about 2 inches or smaller.

I put some pest snails in and only the biggest one is still alive.

I have some kuhli loaches in another tank that I've been thinking about putting in there but I'm worried that the cichlids will kill them.

[Can we give this guy some advice]

http://imgur.com/a/O6QVn69

I'm not really sure what to tell them but they seem to care about their goldfish. It sounds like they're keeping the fish in a 10 gallon which is obviously too small but how big of a tank would they really need for those fish? Also the fish should have grown in size after a year right, or maybe they just have big hands?