Tank temperature fluctuates a lot

bentz69

Hi first post. I setup a 36 gallon bow tank a few days ago and filled it with water, gravel, decor etc. I let the tank run 2 days before I added 6 tiger barbs to start the cycling process.

I have the heater set at 76°. When Im not home (at work for 12 hours etc.) I do not run the air conditioner in my apartment and it gets very hot in the apartment now because its the summer. My apartment will see temps of 90° with the a/c off for extended periods of time.

Ive noticed just in the past few days that the tank temperature will reach 82-84° when the a/c is off for long periods of time.

Can this temperature fluctuation of the sometimes 10° in the tank water pose a problem for the fish? I realize that this change in temp occurs over several hours in time so its not nearly as harsh as say dumping in new cold water.

What can I do here? Should I add a tank cooler? I plan to keep barbs, puffers, sharks and maybe some betas/tetras?

nfored

A tank cooler aka a chiller will cost a nice chunk of money and will cost you as much if not more to run then to cool your apartment to 80f. Fluctuations of such vast amounts like that can be very hard on the fish, that with the hell they are living in while you cycle means one crumby life for those tiger barbs. Now 82 and 84 is no big deal as far as water temp my tank is always at 82 the problem comes when you have shift of more then 5f in a day or several shifts in a day. If the tank is not getting any hotter then 84 and you don't want to run ac or buy a chiller then you could simply bump the thermostat to 82 on the heaters to keep it a stable temp.

Barbman

Do the fish appear healthy? If so then I'd say leave it alone. Now if your AC goes out and you have several 90+ temp days, then you can do two simple things.
1. Run a fan across the surface of the water. It promotes cooling by speeding up evaporation which draws heat away from the water. The downside is that it speeds up evaporation.
2. Ice in a plastic glad bag. You'd be surprised how well it can lower the tank temp. Just make sure it's in a bag and not free floating ... that's potential untreated tap water that could melt it's way into your tank.

The temp swings you've been talking about shouldn't be a big deal for your fish.

Byron

First, may I welcome you to Tropical Fish Keeping forum.

Second, the heat issue. I would suggest it is better to limit the fluctuation as much as reasonably possible. A full 10 degrees every day is significant. The aquarium will usually be the same temperature as the room, or very close; the larger the volume of water the longer it takes to warm and cool of course. Sudden changes are not advisable, which is why I would not use the ice method. Better to let the tank warm to the room. Opening the cover and using the fan is fine provided you don't have fish that are likely to jump--and you'd be surprised at how many will.

Third, I see a real issue with your intended stocking. We have fish profiles here, second tab from the left in the blue bar across the top of the page; if the fish scientific or common name used in the profiles appears the same in posts it will shade and you can click on the name to see that species' profile. I recommend you check out the fish species. I will only point out a couple of issues.

Tiger Barb are notorious fin nippers, and sometimes they can get downright nasty to other fish. Long-fin fish such as Betta must never be in the same tank. Also, a group of at least 8, preferably 12 or more, will usually reduce the nipping/aggression. But this would fill your 36g, as this is sufficient space only for a good group of TB. If you want other fish, I would forget TB. And Betta are not community fish; other fish tend to nip at them, or they attack other fish, it depends upon the species and the Betta's temperament. Puffer are also aggressive and should be on their own; and some require brackish water, others are freshwater. No shark is suitable for a tank as small as 36g, and they are territorial (and thus "rough") to varying degrees depending upon species. Several are in our profiles, under the Cyprinids category.

Cycling. Do you have live plants? This is the best way to "cycle" a new tank. Any other method is highly stressful on the fish, and will lead to internal problems that will affect the fish either in behaviours or health down the road, and in almost every case cause a premature death. The effects of ammonia and nitrite poisoning are substantial, at very low levels. You can read more on this in a couple of articles here, one on cycling itself "stickied" at the head of this section of the forum, here';s a direct link:
A Beginner's Guide to the Freshwater Aquarium Cycle
And the other on bacteria from the Freshwater Articles section, here's that link:
Bacteria in the Freshwater Aquarium
These will help explain the dangers.

Byron.

bentz69

Good advice here. For now Im leaving the tank heater at 80. When it does get a little hotter in the apartment, the fluctuation wont be as severe

Disregard the fish list I made. I was still researching at that point.

Right now I have 5 barbs, 2 dalmatian mollys, 2 bala sharks and 1 iridescent shark. No biting going on and everything looks peaceful for now. Mollys staying close to barbs with no problems that I have seen yet. The 2 bala sharks seem to stay in the rear of the tank and dont do much. The iridescent shark is extremely lively and all over the place. I do agree that this tank is too small for a few sharks but this is my first tank and I already have plans to go bigger. So when the time comes Ill be ready

I went ahead and bought some tetra safe start instead. Before adding the TSS, I changed about 50% of the water just to be safe since tetra states it should be added either right before introducing new fish but can be done at the same. Ammonia was only at .25ppm

I have 2 live plants also