Roach Bombs = DEAD FISH
If I were you I would break down the tank before setting off the bombs, just too risky for your fish.
I've been in the salt habit for the past 18 years, killed my fair share of gorgeous fish - mainly due to lack of knowledge. There wasn't the net around then, NO excuse for that kind of trial and error nowadays. My system consists of a 150 reef upstairs, a 120 reef downstairs and both are connected together with a 100 refurg. Not many corals or fish at the moment- 95% loss of livestock when we remodeled the kitchen ( where the 150 is located) paint fumes impossible to contain given the dynamics of my system. Yes I did cover the tank to the best of my ability, but sps are very delicate.
Thor- Always buy the largest tank you can afford- more volume, more surface area for gas exchange, longer time for ammonia and nitrites to accumulate to potentially lethal levels. Your fish will grow and grow quickly. You should monitor your ammonia levels until they zero out, then monitor for even deadlier nitrites until they zero out - should take about a month for your tank to cycle. Keep you fish population low and don't overfeed. If food doesn't get eaten in 5 minutes net it out or siphon it out or else it will decay and add to your biologocal load - not something you want to do when your tank is new and cycling. You also need to lower the number of fish in a 10 gallon tank to maybe 2 small fish. I believe the rule of thumb for freshwater is 1" of per 1 gallon of water in a fully cycled system. And the fish measurement is based on the Maximum size the fish can attain. My best advice is patience and to read, read, read! Buy some books. The boards that have been listed are excellent, especially for beginners. Listen to the people on the boards, they know their stuff. If you choose not to do what people have suggested for you so far you will not need to buy a bigger tank down the road, you'll end up killing everything you put in the tank, you'll get very dicouraged and quit. I've seen it happen way too often. If you do choose to follow everyone's advice you will be rewarded with a healthy tank with healthy and happy fish. Then and only then would I suggest a larger tank that would support oscars instead of dooming them to an early demise.
Don't get dicouraged, if you need help or advice, just ask. It seems as though there are plenty of people here you can trust and are very knowledgeable. We were all new to this once ourselves.
Kim