@Spizeck I started out with a TG-4 myself, nice little cameras to start out with I think.
Getting constructive criticism is hard... at least I've found that to be the case. So I'll give you my 2 cents, full disclosure I'm not a pro, so take it with a grain of salt.
Are you using a wide angle lens for these shots?
1) I've found scorpionfish to be hard to shoot at least to get good shots, I've never found one that allowed me to get a good angle so that the background worked well with their incredible camouflage. Your shot is pretty good, the best shots I've seen of scorpionfish is when you are able to get low enough or the right angle to get water behind them vs reef since they blend in so well.
2)The reef shark is pretty small in the photo, and it's below you. Fast moving subjects obviously make composition tougher, sometimes they'll swim "laps" around an area and you can try to predict where to be for a good shot, some probably aren't as cooperative. If that's your first shot of a shark though it's pretty good.
3)This is my favorite of the 4. Cool foreground subject, diver in the background, good elements for creating an interesting photo!
4)Who doesn't like sea turtles! Sometimes turtles are very cooperative and make getting a face-on shot easy, some of the best turtle shots to me are CFWA ones where it isn't directly head-on but with a slight outward and upward angle.
The color in your photos look good, don't really see any distracting things like backscatter etc, for being a self-proclaimed newbie these are good shots!