I found this article about a species of crab that lives completely in pockets of rainwater collected by specific plants in the tops of trees in Jamaica... Apparently they have developed a system of maintaining water quality including ph
/calcium buffing and oxygenation.... Strictly freshwater species I assume, but maybe we should have our staff geneticist build us a species to take care of our tanks for us? LOL
"These very unusual crabs, which are the most terrestrial of any in the world, live in little pockets of rainwater inside bromeliad plants, which grow on the branches of tropical trees," says S. Blair Hedges, an evolutionary biologist at Penn State and a member of the research team. The tiny bromeliad crabs are less than an inch long and are thin enough to squeeze between the leaves at the base of the bromeliad plant, where rainwater collects. The researchers say these crabs are by far the most attentive mothers of all known crab species and the only ones known that actively feed and care for larvae and juveniles during the several months they spend in their rainwater nursery. "The mother crab manipulates water quality by removing debris, by circulating the water to add oxygen to it, and by carrying empty snail shells into the water to buffer the pH levels and add calcium," Hedges says.