What can you mix with clownfish and blue tang and what equipment do you need?

Yes you can put a clownfish and blue tang together. Blue tangs need very large tanks however, you will need at least 100 gallons, but bigger is better, 150+ would be preferable, since they grow up to a foot long and they are very active swimmers (whereas clowns only need 20-30 gallons). You will need a basic fowlr set up. So about 1-2 lbs of live rock per gallon, live sand, some powerheads, a filter, heater, saltwater mix, hydrometer, and your test kits. You need to cycle the tank before any fish are added. Protein skimmers are useful but not necessary just for fish. Many other fish can be mixed with them, since tangs are clowns are both generally peaceful, though you should only have one species of clown in a pair and one tang in a tank unless the tank is very large, because that can cause territory issues. Do your research of the fishs requirements to see what else you would want.