Hi, as u can probably tell from my signature i'm planning on getting a betta for my small (6gal) tank, when i buy a big tank for my other fish.

Thing is, when looking for a bigger tank, i find the best deals on the net are complete sets with heater, filter etc included.
eg:Rena Glass aquarium with hood and lighting and 100 watt heater thermostat. 500 l/h power filter. Dimensions Length 80cm x width 30cm x height 42cm tank, with hood fitted 49cm. Contains 85 litres of water.

would it be ok to use the heater that comes with the big tank in the small tank? (assuming it has a thermostat that will keep the temp constant) or it that a bad idea?? just wondering if i can save some cash here and there!! i have read that it doesnt make much difference if the heater is too big for the tank, but i dont know how reliable that info is.

thanks x

It doensn't matter how strong the heater is, it just needs to have a dial where you can 'dial in' the temp you want. Keep a thermometer in there as well to make sure that the temp the heater says is in fact the temp the water is.

thats really good to know, thanks, might save me a bit of money in the long run

I have a 25 watt Hydor THEO heater in my 6 gallon betta tank... It works great. The temperature stays very stable, and because of how the heater is made, you don't have to worry about it burning your betta.

Actually, in tanks under 10 gallons you need to be very careful that the water doesn't get overheated! If you choose to use the larger heater in the smaller tank make sure that you have a thermometer set up to check on the water heat FREQUENTLY! A 100 watt heater is very large for 6 gallons though.

thats what i thought. well, i'll shop around a bit first, got a while til i can make any purchases anyway. i'll prob be askin more questions about this in a couple of months. thanks.

Feel free to ask away, we are all here to help.

What temp. do bettas need to be kept at?

Ideally 77-80 degrees Fahrenheit, but they can survive in 70-85 degree water.

i'm probably just going to get a small heater seperately, coz i dont want a boiled betta! and evidence suggests too cold is better than too hot, so dont wanna risk overheating

Either a 15 or 25 watt heater is the correct size for a 6 gallon tank

yeh thats what i saw in the shops, about £18 i think. will have to start saving up if i want that, another tank and filter and a betta!