Is Fish or a Can of Tuna REALLY THAT Bad for You Your Kids GreenLifeSaver. net BlogPlants are extra a good idea since they raise oxygen levels in the water. Goldfish kept in bowls or “mini aquariums” suffer from death, ailment, and stunting, due essentially to the low oxygen and intensely high ammonia/nitrite levels inherent in such an atmosphere. In assessment to other common aquarium fish, goldfish have high oxygen needs and produce a big amount of waste due to the fact they lack a stomach; therefore they require a considerable volume of well filtered water to thrive. In addition, all goldfish varieties have the abilities to arrive 5 inches 12. 7 cm in total length, with single tailed breeds often exceeding one foot 30. 5 cm.