Freshwater invertebrates

Right now, the only freshwater invertebrates we sell are limited to an assortment of shrimps and snails with crayfish, mussels or clams occasionally available.  Most other freshwater invertebrates are going to be too difficult to keep (sponges), are too dangerous for fishes (many insect larvae or pathogenic worms), or are too small to avoid being eaten (daphnia and Cyclops).  Generally speaking the invertebrates are a bit more sensitive about water quality that the fishes.  Also anything with big claws is usually going to be predatory on any other animal it can catch.

Keep in mind that many of the medications that will cure fish diseases can be toxic to the invertebrates you may have in your tank.