4 Feeding Your Fish for a Clean Tank. How you feed your fish also plays a role in how easy is it to keep your aquarium clean. Different fish have different diets: some eat other fish, some eat veggie diets, and there is a wide variety of flakes and pellets to keep your fish from starving to death. Con1 Zoos don't educate the public enough to justify keeping animals captive. A review published in Animal Studies Repository concluded, "to date there is no compelling or even particularly suggestive evidence for the claim that zoos and aquariums promote attitude change, education, and interest in conservation in visitors." Tanksetup: Betta fish need a five-gallon tank, or larger, along with a good water filter and heater. A low-level air pump can help to oxygenate the water, but remember that bettas prefer still water. Habitat and maintenance: Bettas like having places to hide. Put decorations, including live plants, in the tank. Iskeeping fish in tanks cruel? if you care for them properly, it is not cruel. Most fish kept in aquariums aren't at the top of the food chain and don't have the best life expectancy. They have a better quality of life in an aquarium than they do in the wild. Hereare the best freshwater fish for keeping an aquarium clean: 1. Clown Pleco - Panaqolus maccus. by Chubbs. Maximum size: 3.5 inches (7.9 cm) Tank size: The fish is not very active, so a 10-gallon tank is appropriate: Temperament: Peaceful: Water Temperature: 77 to 85 °F or 25 to 29.4 °C: Thereis a debate on whether it is cruel or not to keep fish in aquariums. Some people argue that aquariums provide a safe and controlled environment for fish to thrive, while others argue that fish belong in their natural habitat and should not be kept in captivity. Herere your options: A: Tensed and stressed. B: Relaxed and peaceful. It's option "B", Of course! So that means a fish aquarium can - and in fact does - act as a mind relaxing tool and a peaceful mind is the first thing that you need to have if you want to live your life with happiness, abundance & prosperity. Thesestunning fish reach lengths of up to 15 inches, however in captivity they usually grow to around 12 inches. 1. Mandarinfish. These spectacular looking fish are the most beautiful in the ocean. It is native to the Pacific Ocean and lives in sheltered lagoons and inshore reefs. dR9ZPu.