my kids do them every year. we love them. they only last a short time but we got ours to last a few months. I also do water changes on there tank like I do with fish, we also put an air stone in there tank. we use a 5 gallon tank for them and add some gravel and some plants. there cute and my kids love them./ when I do water changes on there little tank I just take out water, then add fresh tank water from my 55. they do real well this way.