Yeah - actually you could only keep juvenile Bamboo sharks, Eppies or Horn Sharks in a 300 gallon tank. But for the adults - a 300 gallon is too small - not enough space. But generally speaking most Bamboo & Epaulettes need at a tank or pond that is least 500 gallons or more. For most of the available Horn shark species - at least a 1,000 gallon tank or pond, for life.
As for Catsharks - it all depends on the species. A small species like the Cloudy or Izu catsharks can actually be bred in a 300 gallon tank.