User:Rmarin8/Pond loach

Physiology
Unlike most other fishes, the pond loach can burrow into and hide in soft substrates, breathe atmospheric air if necessary, and survive for long periods of time outside of the water. For the pond loach to survive on land for extended periods of time, it has physiological adaptations to reduce toxic ammonia concentrations in the body and maintain homeostasis and normal functioning of tissues. When on land, the pond loach can suppress protein breakdown and catabolism (which avoids creating ammonia), switch to partial amino catabolism (which creates non-toxic alanine instead of ammonia), convert ammonia to non-toxic glutamine, and get rid of ammonia by excreting it as NH3 gas. The pond loach is also relatively insensitive to ammonia, though it is not known how pond loach’s tissues, especially the heart and brain, are able to function at ammonia concentrations that would be lethal for other species. One hypothesis is that the pond loach may maintain normal brain cell functioning by altering the sensitivity and specificity of receptors in the brain for potassium ions, which otherwise would be overwhelmed by ammonia.