Any living aquatic creature can have its growth stunted. However, the results are usually an early death due to nitrite poisoning (methemoglobin development aka brown blood disease). The disease progresses in animals forced to live in enclosures too small to properly house them and they inevitably have to live in their own waste products. Over time methemoglobin displaces normal hemoglobin blood cells which causes a deficiency of healthy cells that bring oxygen and nutrients to all cells and carry carbon dioxide and waste materials away from all cells.