I'm going to agree with most of you
1. Coloured rocks... Why? Sand looks sooooo much better (or at least natural stone or white stone!)
2. Goldfish in small tanks (well any fish in a small tank). Who in the right mind made up the myth that they can live in those tiny plastic tanks (you know the ones with the goldfish pictures on them? But they look like something little kids put bugs in...)
2. People idea on betta fish. No. They ARE NOT some fish who should live in a bowl, and those stupid tanks with the plant on top.... No. Berta's can't live off roots. Idiots.
3. People not researching. Oh you want to put your cichlids with your guppies? I was selling some cichlids and some person was like I have a 20 gallon with guppies and wanted to add something else to make it look better! Bye guppies
4. People who don't cycle there tanks. Or believe letting it sit for 24 hours is "cycling it".
5. Low water levels. Nuff said
6. Algae on the front glass. Sometimes I let the algae build up on my back wall and my rocks, to me it makes it look natural. And my fishes graze on it.
And one more, it has little to do with looking at people's tank, but still; uninformed employees. If you know nothing about fish.... Maybe you shouldn't work in a fish store (or at least not give ridiculous advice)!