Is my tank crowded?

[andyjs]

Thanks man, I really appreciate it. Everybody was telling me to pick up a AquaClear 70. I went and bought the 50. I have a 20 gallon tank so it should do the trick right?

Another question, will it harm my fish by putting a new filter in there? Since I'm essentially putting a sterile filter in there with no bacteria cultures, will the ammonia spike again?

If there's room, keep the old filter on for a week or two after you add the new one. If not, just take any filter media from the old filter and try to find a place in the new filter to fit it to help the bacteria transfer