Hello,
Here is my problem.

I am living in a tropical region (West Africa) and have a nice tank with some local plants and few fish.

My concern is that due to the climatic conditions by night the water temperature drops to +/- 24 C and late afternoon it can rise to 30 or 31 C.

I have noticed that when the temp gets to 30 C one or two of my Black Mollies start swimming 'strangely' as if they shaking their body in a perpetual 'NO' sign.
None of them died and also their off spring is growing wel but I am worried.

I was thinking last Sunday when the temperature started rising in the afternoon to serve them small amounts of cool water but I am not sure this is a good idea?

All ideas are welcome.
Thanks,
Marc

__________________
100 Gallon tank (work in progress)
2 x Fluval U3 filter + DYI CO2 + 40W 'Grolight' + 2x28W 'warm white'

3 Bala sharks + 2 Angel fish + 2 Black Mollys +1 Orange Platy + Plenty of Molly fry, baby's & teens

Egeria Densa, Cryptocoryne petchii "pink", Urticularia Graminifolia and African waterweed

Those large temperature swings are stressful to the fish you are keeping and the high temps are bordering on lethal for your mollies. I would suggest placing them in a larger tank as a larger body of water wouldn't heat up as quickly and would keep the temperature more reasonable. Other than that you would need a chiller to keep temps down. As for adding cool water to the tank, I believe that the swing in temps and changes in water chemistry would just increased the stress on your mollies. Also make sure the tank gets no direct sunlight. Hope this helps.

Thanks for your reply.

Bigger thank is not an option for the moment.
Unless I get my (bigger) house finished there is no space available.

Ok, if the temp. swing is the issue here I may install a small aircon in the room and let it run during the day at let's say 25 C. Will that help ?

Chiller may be a better solution but then again I have to import it from Europe and that is not easy from here and will take time...

Can a ceiling fan or standing fan help if it is blowing some air over the water surface?
Sorry but I am just trying to find a solution for tomorrow, before disaster strikes.

__________________
100 Gallon tank (work in progress)
2 x Fluval U3 filter + DYI CO2 + 40W 'Grolight' + 2x28W 'warm white'

3 Bala sharks + 2 Angel fish + 2 Black Mollys +1 Orange Platy + Plenty of Molly fry, baby's & teens

Egeria Densa, Cryptocoryne petchii "pink", Urticularia Graminifolia and African waterweed

The air conditioner will help as will the ceiling fan. Air moving across the surface of the water will help cool the water through evaporation. Also water movement at the surface of the water will help so point your filter outlet towards the surface of the water if you can. If you have an air stone bubbling in your tank that will help too. Good luck my friend.

Hi Willfull,

Left today a standing fan blowing gently over the water ( don't like to much the hood off) and max. temp. today was 82 F / yesterday it was 86 F.
Mollies are looking 'happier' also.

The plan this week-end is to cut 2 holes in the hood and fix 2 recup PC fans in it.

Any toughts ?
Thanks

__________________
100 Gallon tank (work in progress)
2 x Fluval U3 filter + DYI CO2 + 40W 'Grolight' + 2x28W 'warm white'

3 Bala sharks + 2 Angel fish + 2 Black Mollys +1 Orange Platy + Plenty of Molly fry, baby's & teens

Egeria Densa, Cryptocoryne petchii "pink", Urticularia Graminifolia and African waterweed

I'm glad the temps stayed lower and your mollies are surviving. The PC fans are a good idea and if you can try not to have the lights on above the tank as that will also heat up the tank during the day.

If the room gets plenty of ambient light, no need for the aquarium light to be on for more than feeding time...unless you have plants in the tank. PC fans work. I've seen pics of people that have done it on other sites. You may just want to remove the hood completely and just set the light up there when you need it. How long before it gets a little cooler there?

My tank is heavily planted. I like the green, and it is a good hiding place for the Molly's and Platy fry.
Basically I have 2 plants: Egeria Densa and African waterweed and they only look 'green' with a lot of light.
I got both of them out of a local streem (Densu river) and they where bathing in sunlight where I got them.

I will probably have to find a good equilibrium between light and temperature.
I will still think about it but maybe I will set the timer to switch on the lights from 5.30 to 11.00 AM and then again from 5.00 to 8.00 PM.
Will this less bright period in the middle of the day have a negative impact on the fish or plants?

When will it get a little cooler?
JAN to APR : very hot, dusty and dry.
MAY to JUL : cooler and rainy.
AUG to NOV : hot and dry.
DEC: a bit cooler with showers.

I don't have a choice, I will need to have a working setup within the next 2 months, providing light for the plants without getting the heat from it.

Thanks for your support,
Marc

Update al this kind people that gave me lot of good advice: I have now a 100 Gal tank and I think because of the huge volume of water the temp is now stable at 81 F (27 C). Problem solved! Thanks to all.

__________________
100 Gallon tank (work in progress)
2 x Fluval U3 filter + DYI CO2 + 40W 'Grolight' + 2x28W 'warm white'

3 Bala sharks + 2 Angel fish + 2 Black Mollys +1 Orange Platy + Plenty of Molly fry, baby's & teens

Egeria Densa, Cryptocoryne petchii "pink", Urticularia Graminifolia and African waterweed