Fish may not have long memories, but they do have instinct. While most fish values their own life and will hide behind rocks when scared, some tend to freak the F out when you walk past the tank late at night like a giant predator ready to chomp. Now, some of these freaky-fishes are some of the most beautiful specimens in this hobby and of course, everybody knows we ALL want to own the pretty fishes. I mean, why else would there be justification for spending thousands of dollars MORE just so you can maintain a habitat to keep the more colorful saltwater fishes? Anyway, since you have decided to take the plunge and you are now the caretaker for these fine animals, you should know how to keep them in the water so they don't unexpectedly go carpet surfing or be your dog's late night snack.
For those of you with canopies, you can probably skip this post. I have an open top with a light on stands so for me, I had to find a way to cover up the top of the tank while allowing air to circulate and not to trap the heated air in the tank. The picture here shows a light eggcrate which you can buy from Home Depot. My girlfriend thought it was hilarious that I called it an eggcrate since a few of the employees had no idea what I was talking about, but they are actually called eggcrates and labeled as such on the shelves. One sheet allowed me to cut two pieces for the openings I had over my 90 gallon while still having some extra smaller pieces for frags or whatever usage I may have for it.
Eggcrates are pretty easy to cut, in fact, any needle nose plier should be sufficient for cutting out the sections you don't need. For my tank, I measured out the length from front-to-back and side-to-side on the top where the eggcrate would fit and then I cut out a giant rectangular piece to fit the opening. If you're doing this for a similar sized tank, make sure you cut it in a way that will allow a second piece to be cut from the main sheet after the first one is cut out.
Once the main cuts were done, I slid the eggcrate over the top to make sure it'd fit, but I'd imagine many of you like myself would have pipes and stuff near the back that would prevent the eggcrate from having a perfect fit; so the second step in this process is to cut around the tubes in the back so the eggcrate can sit on top nicely.
For measurement, I pretty much eyed everything and used a sharpie marker to mark the points where I would make the snip. Once things lined up all the way across, I cut away all the back sections and slid the eggcrate all the way back to make sure it'd fit. I can gladly say everything was a perfect fit.
After a couple of days or so, I got the feeling that the eggcrate was reflecting too much light away from the tank. While I couldn't really tell visually if the PAR in the tank had dropped, I could tell on my ceiling that a good portion of the light was reflected onto it; at least a lot more than before. You can also see in the first two pictures the areas where my MH lit up and most of that I feel was wasted on the eggcrate instead of it being on the corals. Therefore, as part three of my project, I decided to take a chance and cut out just the middle where the lights are and hope that if by chance my fish jumps through the surface in the middle that it will at least hit the light and fall back straight down.
The finished product is basically a tight fitting hood that allows gas exchange, temperature regulation, fish safety and a piece of mind. While I did not expect my wrasse to jump at all, there were a few times that he freaked out for no reason and was saved by the hard safety net.
Overall, if you are in this hobby and have some expensive livestock AND have an open top, I would highly recommend adding an eggcrate top to your setup. It doesn't look ghetto and most people don't even realize it's there but you'll sleep soundly knowing that your dog won't randomly walk up to the tank, scare the fishes and land himself some unscheduled snacks. Mmmm speaking of snacks... I should get some.
