I cannot tell you from firsthand experience, because I've never tried. But one problem I can forsee is the Mudskippers though... they'll need thier beach like environment, or some land to be able to crawl up on to. With such requirements, the water will have to be rather shallow, and so decreasing your water volume. As such, the water won't retain heat well and can pollute very easily. The only way to overcome this is to have a very large tank....