Do my Hillsteams need to be cooler?

[Jaynie]

Hi Everyone

Here in the UK we're having a mini heatwave and I'm slightly concerned about my loaches. I usually keep there water temp at 20oC but due to the heat their water is creeping up to around 24, and its not even summer yet!! Is this too warm for them? If so how could I cool the water. I've tried a desk fan near the tank (not pointed directly at it) and this made very little difference if any.

I must add however that they dont seem at all bothered about the heat and are all there usual selves, but I am concerned that any warmer could be bad and want to be prepared.

Thanks in advance for any replies

Jayne

[Mad Duff]

I use a small fan on my river tank in the summer, if the lid is opened and the fan directed at the water surface it will take a while but will start cooling down, the only down side to this is the fact that the water evaporates faster than normal so I make sure the tank is topped up every night.

I have found the best way is to keep an eye on the temperatures and when it gets down to just below were you want it stop the fan and then keep an eye on the temps as they come back up and see how long it takes to drop and then rise to a set temp. After that you can rig the fan up on a timer and have it to switch on and off for set periods and this helps keep an almost constant temperature.

[janma]

What hillstream loaches do you have in there?

[Jaynie]

3 P. Cheni and 1 G. Occelatus

[Cup]

imo, 24c is fine.

[Jim Powers]

I really wouldn't worry about 24C either.
I have a few hillstream tanks and they are all in that temp. range primarily due to the heat sink created by the pumps.
Just make sure that you keep the O2 levels high and you should be okay.
If you want to bring the temp down a couple of degrees during extra warm periods, the fan method works well.

[Jaynie]

Thanks so much everyone for your replies.

I've just set the fan up again next to my tank, unfortunately i'm unable to keep the lid open as the lighting is integrated in the lid, so have just opened the feeding flap. I'm sure that by keeping the area around them cool the temp will slowly decrease.

Just out of curiosity what is the maximum temperature these loaches can cope with?

[Jim Powers]

I really don't know about the maximum temp. I do know that some people here have had their tanks get 28C or so for short periods of time during heat waves. I think the key words here are "for short periods of time". I don't think they would survive such temps over the long term. Remember, that the oxygen levels will decrease in water of higher temps.

[Cup]

In the summer, my tanks usually level off at 78 degrees. Granted, these days, I only keep gastros and sewellia, and they are quite hardy.

[Emma Turner]

Jayne, if the temp looks like it is creeping up a bit too much, I would leave the tank lights off as they will be adding heat to the tank. Obviously in a heavily planted tank this wouldn't really be possible, but most river tanks do not have so much in the way of demanding plants. Then you'll be able to open the hood and use the fan over the entire surface.

My river tank is running very hot at the moment (84-85 deg F ), but I do not have any Gastromyzons in there. The fish I do have seem to be able to manage with the odd spell of hot weather as the water is so highly oxygenated, but obviously this isn't ideal.

So Steve just bought us a portable air conditioning unit for the downstairs of our house, as not only do I have the river tank that really musn't get too hot, but I have a tank with a large group of rare cool water Schisturas that I cannot let get too hot either. I'm going to switch it on now as the tank temps are getting to warm.

Emma

[janma]

I mentioned this in another topic, but I e-mailed Dr Tan about the temps. In short: gastros can take higher temps than recommended. When I told him I had my tank at 24C, he thought it sounded cold. But the best way to measure was the way fish behave, eating etc.

Also a Finnish guy wrote that he had been to Borneo and has a friend there who catches gastros, say that they live in water warmer than 28C. So they can take warmer temps, so there is no need to panic when it gets a little hotter in the tank.

[Jaynie]

I'm beginning to wonder if I've actually been keeping my tank too cool in the first place. I was under the impression that it should be around 20C, is this too cool?

At present with the lid open, lights off and by keeping the room cooler the water is about 22C now.

Emma your fish are so lucky that they get aircon, there's no wonder your fish always look so happy on your pics, they really are amazingly well cared for in every way

[Jim Powers]

I used to keep my hillstreams around 20-22C (68-72F) in my original river tank until I added more pumps. The heat sink from the pumps raised the temps into the 24C (75F) temp range where they remain today. I have not noticed any difference in the activity levels or health of the fish.
If it were me, I would stick with the temp that was easiest to maintain, as long as there was sufficient flow and oxygenation.

[Martin Thoene]

I've had River-Tanks go up to 80F on several occasions and noticed no change in behaviour. As Jim says, and I've always maintained, Oxygenation is the key to keeping these guys healthy.
Many of our friends in Borneo and other places have reported quite cold temps in rivers frequented by Gastromyzon......cold enough to make them uncomfortable on initial wading in.
Due to the generally shallow nature of the native rivers it's possible that temperatures go up and down with the sun in exposed areas. Tropical rains cause rapid changes too. I've always believed that these fish are actually capable of withstanding fairly severe changes in water parameters as long as it doesn't happen really rapidly like moving a fish into completely different pH and temperature water. That will obviously cause osmotic shock.
For cooling, the fan method is absolutely the most effective and cheap method.





You can get a lot of surface agitation.



Martin.