Temperate/Subtropical Fish?

I just got a 65 gallon tank (4ft x 1.5ft x 1.5ft), which I was originally going to stock with three goldfish, but I have decided not to go that route.

I'd like to stock it with smaller temperate/subtropical fish that can be happy with the temperature changes of SE Queensland, as it will be unheated. The tank is outside and in shade for most of the year, with some dappled sunlight for a few months in the mornings in summer. The temperatures here can range from high 90s (*F) to low 60s/high 50s.

As the tank is so big and in the shade for the majority of the year, I don't expect the temperature of the water to fluctuate as much as the air temperature. The substrate will be half gravel and half sand and the tank will be heavily planted.

I was thinking zebra/leopard danios, white cloud mountain minnows, and rosy barbs (maybe). I know of people who keeps these varieties in ponds in SE QLD and northern NSW. A lot of people also keep platies and guppies in their outdoor ponds here, so I may be able to source some of these as well, since they'll already be used to living outdoors.

Do you have any other suggestions for fish for an outdoor tank?

 

65gal without any geothermal insulation is really a puddle. I really do wish you luck, but with a temperature range as wide as you have given, I doubt much will do well in there. You could easily experience swings of 6-10deg (F, I don't know C that well) in the space of any 24 hour period.

 

The temperature range I gave was summer highest temps and winter lowest temps on average. There are many people in the same city as me that keep unheated outdoor tanks/bathtubs and above ground ponds with the same fish and they have no problems, so I assumed I would be the same.

 

Ok. If it's working for them, then I wish you well and look forward to seeing your results. I'm hardly an expert. Hopefully someone who is will see this.

I don't know who to refer you to, but chromedome52 is a fish wizard and he was on a little bit ago. Maybe he can help or refer you to someone who can.

 

Thank you, .

I want to make sure I only have suitable fish for my climate, so I'm going to go to a small local pond/garden store that stocks mainly natives and pond fish, so I'll ask their opinion on the best fish for my situation. Hopefully, they can help.

 

Usually a pond is better insulated on the sides through the earth around, don't know elevated ponds though. Bathtubs as well have a better insulation than a glass tank around.

The problem is that your glass tank will cool it down in the winter months too much. The higher temperature will most likely only result in a bit of lethargic fishes where the colder temperatures can make health damage. I'm not an expert but through my engineering background this appears logic to me.

If you could insulate the 4 sides of the tank over the cold months and leave only the top open, you would have a kind of pond and it could work.

 

Thanks, Wolf65. Do you have a recommendation for insulation for the outsides? Would styrofoam work? I have styrofoam underneath and it's up against a wall.

I'm going to the LFS on Monday, so hopefully they can suggest some fish that could be suitable. I know they have lots of natives that they use in ponds and outdoor tanks here and further south (colder). They have a wonderful selection of rainbows and blue eyes. They also have regular and golden white clouds, which are the fish I most want.

 

I think styrofoam would work, but don't glue it as you want it off in the summer. I think your idea is very nice and I hope it works out fine

 

Australian Rainbows are from your climate. Extremely hardy fish

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