pair of guppys will eradicate the promblem.
Can you net the mosquito larvae and feed them to smaller fish? That would solve that problem quickly. To solve the problem all together, you should try to get more water surface agitation in your tank. The adult mosquitoes need still water to lay their eggs. The larvae also need still water to breath properly. You can also keep an eye out for the egg cases that they lay. They look like little brown floating rafts which can be taken out and thrown away.