You can’t judge a local fish store by its exterior appearance, but you can certainly do so by its display aquariums. I visited a few local aquarium stores very recently and I was exposed to both ends of the aquarium spectrum. On the one hand, I was blown away with a couple of very mature reef tanks, full of huge colonies of Acropora corals, chalices, and healthy looking fish. On the other hand, I found tanks that could barely classify as reef aquariums and they contained algae overgrowth and parasites. I realize some aqurium issues are hard to avoid, but when a display tank is overgrown with algae and full of fish that you know shouldn’t be together, you might want to turn around and walk out the door. A display aquarium is supposed to show off what all of the hard work and dedication in this hobby will get you. It’s not supposed to be neglected and a display of store’s incompetence.
When visiting any fish store, be sure to play close attention to their fish and corals. Don’t just look for the livestock you want, but look at everything. Check for visible parasites, or their aftermath. For example, Acro Eating Flatworms (AEFW) leave a very distinct path of destruction. The worms are nearly invisible, but they leave small white circular marks on the spots where they were feeding. Other parasites are not so noticeable. Red bugs for instance are very tiny and don’t leave any significant tell tale signs of their presence. You just have to very closely inspect the corals before making your purchase.
Fish might be a little more difficult to diagnose prior to their purchase. Many fish can have parasites that are internal, or haven’t exhibited an external form yet. Ich is a notorious parasite in the aquarium world and it has several life stages. One of these stages is a highly visible cyst that can usually be found on the fins and body of any marine fish. However, it also has a free-swimming form that is invisible to the naked eye. How do you know you haven’t picked up a fish parasite? Well, you honestly don’t. But you can select healthy looking fish from a store that appears disease and parasite free.