PetCo is having dollar per gallon sale.Could you recommend a good inexpensive filter, heater, and good for a 29-40 gallon?
Just remember goldfish do best without heaters. Hope someone else can come along and recommend a filter for you.
i use aqueon quiet flow no problems. also aquaclear is something u can look into. also instead of buying filter cartidges get a sponge and that will work as filter media just do ur research with that. or just ask me and i can explain. with goldfish the bigger the better for sure!!!! they produce a LOT of waste
If you do a walstad method tank with plants that would look awesome and you can but lots of plants or just buy some and propagate until you have how ever many you need to filter the tank.