Thank you for your replies.
Tropical Girl - I have two boys at the moment they are in 3 gallon plastic tanks - one in the bedroom and one in the kitchen, both are filtered and heated. My husband has agreed to me having my dream yellow betta in the lounge, but I have to have a nice looking tank as it will be more on display, and I thought these looked quite cool, but I just wanted to check they would be ok for the fish. How many do you have.
Jennybugs thank you so much for the picture it gives me a much clearer idea of what they look like. I do regular water changes for my other boys so that won't be a problem. You can see the fish really well, which was one of my concerns, and I can get a little heater in so that is ok. He looks adorable in there.