Q. I’ve been looking around a fish dealer and found two fish I would like to keep. The fish I like are called the nurse shark and the banded shark. I have a 20-gallon high marine aquarium with a box filter and undergravel filter. Would I be able to keep these types of fish? Exactly how big do these fish grow? Are these fish true sharks? Would I need a bigger aquarium? If so, how big? Any advice would be very much appreciated.
A. Don’t do it! That’s my advice. First of all, a 20-gallon aquarium is too small for any shark (the two species of sharks you mention are “true” sharks — that is, they are members of the subclass Elasmobranchii)! Even those sharks that attain smaller sizes and are well-suited for captive life should be housed in aquariums of 180 gallons or more as adults.
The banded bamboo shark (Chiloscyllium punctatum), which is sometimes referred to as the banded shark, is one of the better aquarium species. However, even a newly hatched individual (they hatch at about 5 inches long) should be kept in an aquarium of 30 gallons or more, and this would be a very temporary home.
Other suitable aquarium species are the whitespotted bamboo shark (Chiloscyllium plagiosum), epaulette shark (Hemiscyllium ocellatum) and the coral catshark (Atelomycterus marmoratus). The nurse shark (Ginglymostoma cirratum) is a terrible choice for the home aquarium, not because smaller individuals will not readily acclimate to captivity, but because they can reach a maximum length of 14 feet!
And don’t be fooled into thinking that public aquariums are dying to take a pet shark from you when it outgrows its home — they are not. So get a bigger aquarium and select one of the shark species that are better suited for the home aquarium. Good luck.