For starters, that tank would never hold a sea turtle for long, they get way too big. Sea turtles are endangered and protected, so its not legal to own one as a pet.
A saltwater viavrium is a lot of fun, I've done that before. There are actually a handful of fish that can work very well in a saltwater vivarium, and if speaking in terms of land critters, the mudskippers are awesome for that. They are technically brackish, which makes things easier and less "exact" than saltwater, and just as much fun. In a vivarium like that, you're also looking at the anibleps (not to be mixed with mudskippers), which can go full saltwater if need be. There are fish such as scats, puffers, knight gobys, bumble bee gobys, and chromides that can all be kept in brackish conditions in a vivarium if the water level is deep enough and enough filtration is offered. Important to note that in saltwater, even with a vivarium, circulation is extremely important, so plan at least 1 power head besides filter. Because vivariums tend to be heavily planted, brackish would also make this easier. Java fern and anubias can be acclimated to brackish conditions if its done slowly enough, as can some of the crypt plants. Crypt wendtii is one that can grow amphibias, up out of the water. Mangrove are also popular for brackish and saltwater vivarium situations, and will also need to grow up out of the water, where only root system & lower part of plant is submerged.
Anyone who wants more details about salt or brackish water vivarium, please start a new thread so it's easier for everyone to find the topic and follow it.
Tracy, thanks for the compliment! He's really a sweet little guy. I also like pets I can touch, and is why I pet my fish and play with the salamander quite often. A salamander isn't quite as delicate as a newt, and they do come out of the water to dry out a bit now and again. A newt must stay wet, the salamander, I just keep my hands wet and he does fine. Since the revamp of his tank, he spends a lot more time out of the water now, exploring every place he can find between plants and glass and rocks. He has done some rearranging of his own, but as the plants are taking root (nicely, too!), he's settling them into what will become their permanent location in his tank. Surprisingly, the 4 leaf clover plant is doing best of them all. Rob put a tri lux bulb in the fixture for me, and it is thriving. It it continues at this rate, I'll have plenty of plants to trade in about a month or so. I may replace the micro sword with java moss because that seems to be where the salamander likes to "bed down" the most.
Fish_4_all, what you're probably catching on nightcrawlers is mudpuppies... unmorphed salamanders. Axolotls tend to be native to the Great Lakes area, with colder water and climate. The axolotl is no different than a mudpuppie other than it never morphs into a salamander, and prefers colder water all the time, where a salamander and mudpuppy can thrive in slightly warmer water. Mudpuppys morph at a slow rate, so can stay in that juvenile stage for years before turning into salamanders.