What aquarium fan is not in awe of freshwater fish and invertebrates? With over 32,500 species known so far, fish outnumber all other vertebrate groups – amphibians, reptiles, birds, and mammals – combined! Perhaps even more surprising is the fact that, although liquid surface freshwater makes up only 0.3% of earth’s total water, over 15,000 fish species call it home! Indeed, more fish species have been found in the Amazon River than in the entire Atlantic Ocean (please excuse the exclamation points - I can’t stop)! Yet fish diversity pales in comparison to invertebrate numbers – biologists cannot even guess as to how many species there are, but they make-up at least 97% of all living creatures. Of these, a huge array of freshwater snails, crayfish, shrimp, clams and even insects - many rivaling the colors of marine species - make fascinating aquarium guests.

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