upgrading my tank

[saltwatertank]

i have had a 10g tank going for almost a year and it is doing great. the only fish in it are a clownfish and a firefish. i want to upgrade my tank to a 20g but i'm not sure how many more fish it could hold. any suggestions?

 

[Sniperhank]

A 20 gallon tank would be close to hitting the max with the fish that you already have. If there weren't any issues with aggression you could possibly add another fish if it is one that stays on the small side. Any more than that and you could start having issues with territory, aggression, and unnecessary fish deaths/expense.