What is the highest temperature you have kept reef fish in?

[Peace River]

IME Caribbean corals seem to tolerate the heat more. I have kept Florida native saltwater fish at 90 or higher for short times.

 

[betareef]

A 90 degree tank with “high water movement” or with an air stone will still tend to smother your fish. It’s not the exposure to air it’s the fact that hot water has lower dissolved oxygen and can’t raise oxygen levels in it.

Completely agree that high temperature will do this. I was only questioning the assertion that an airstone will make any difference given the existing water movement.

Monitoring the tank in it's new position with the top cracked open (don't have the fan yet) and temperature has fallen to 86 degrees, and still falling I assume.

 

[betareef]

If it’s out of direct sunlight then that will help immensely. Also, why closed top? Can it be opened?

It is a self contained tank with a lid to stop fish jumping out. The light is buiIt into the lid, so it has to remain at least partially closed. I have opened it a few inches and put a wedge under it to keep it there. Long term, I will drill hole(s) and add a fan.

Do you have a sump? A fan across the sump really helps. If there’s a canopy then a fan extracting hot air will also help.

No sump.

Look at what’s creating heat. Lights? Maybe switch to black box cheap LED.

That's what is already under the lid. It does run warmish and the heat would be building up. That combined with the summer temperatures is very likely the cause, yes.

 

[Gumbies R Us]

I've had my temperature hit around 81-82 before, didn't have any issues with it.

 

[Dragen Fiend]

82F was the highest but only for a few hours during peak summer days. Otherwise a crisp 78F as usual.

 

[GARRIGA]

May have missed this but is the light off? Floating ice cubes in a zip lock might help.

Air stone won't necessarily increase gas exchange but might help speed up evaporation until a fan is added which will cool the tank. Just have sufficient top off. BTW, fan doesn't necessarily need to be hitting the water and aimed at the the tank might help just getting hot air above to dissipate.

 

[Sawacoral]

Steps are being taken, literally. I have moved the tank, just this morning, away from a window and western side of the house, to a mid-position. Now watching the temperature and even looking at cheap chillers from Amazon

Those clamp on fans will do wonders

 

[bobnicaragua]

Can you cut some holes and run computer fans?

These are water proof and wouldn’t look bad on top of a tank. The more you can open up your canopy, the better.

I’m running metal halides in a canopy. At 75 degree room temp, my tank will stay around 80 with fans. I have 4 holes ontop with computer fans a couple small usb clip on fans.

https://a.co/d/iXF1fUN

 

[betareef]

Can you cut some holes and run computer fans?

That is the plan. Fans will be here soon.

 

[Sdbuehler1]

I ran a mixed reef tank with metal halides about 10 years ago and it regularly hit 84 in the summer with no loss to any livestock or corals. The lights were hanging with no canopy so I put a clip on fan over my sump instead and that kept it from getting too warm. Before adding the fan I think I hit over 86 a few times.

 

[betareef]

Temperature this morning is 84 with the top raised an inch or so all around to allow heat to escape. Fans arrive in a few days.