i bought this new 30 gallon aquarium 2 weeks ago or so, the whole system is new with live plants and everything. i filled it with water and left it the whole day till i got the right temperature, so far so good. then i bought 4 fish, 2 tiger oscars and 2 red parrots. since i put the fish in the tank i always had these bubbles on the surface, its like some one put soap in it but when you open the top hood and blow they go away for a few mins. its been like this for alittle over then 2 weeks. is there any thing i can do?? would it be good if i change the water? can you help here .thanks for now hear from you paul