How Hot is Too Hot?

[DirtyPaws949]

Hey all!
I have several aquariums outside. Most have been there thru summer months the past 1-3 years without issue. The 180gal is galvanized steel, and is usually pretty temp stable once I figure out the right thermostat “max”. I had to do some water changes to err on the side of caution after reaching 88F.

Newest tank is 65 gal glass, and about 2.5’ off the ground on its stand. It is subject to full sunlight from a couple hours after sunrise til sunset (currently). I’m worried about when it actually gets hot out.
I do have an umbrella that I used for shade last summer, and can rearrange it throughout the day (if I’m home) to help control temps.

I try to keep the tropical fish at temps no higher than 84F and have found lower temps cause them more distress than higher temps. Right now the 65gal is at 88F. The fish and snails are eating & playing with gusto, and behaving normally still.
Granted, I have the thermostat cranked up since nights can dip 45-55F, I use the extra heat generated throughout the daylight to keep temps and 75F minimum thru the nights. However, summertime when outside temps are 85F+, in addition to the sun beating down on it, I’d like to know just how hot is too hot, and requires emergency water changes?

Stock:
Angelfish
Yo-yo loach
Rosy barb
SAE
Corydoras
Snails (mystery, ramshorn, Nerite, MTS, pond—love them in planted tanks!)

 

[eon aquatics]

is 86 degrees too hot?

 

[Joshuakahan]

Hey all!
I have several aquariums outside. Most have been there thru summer months the past 1-3 years without issue. The 180gal is galvanized steel, and is usually pretty temp stable once I figure out the right thermostat “max”. I had to do some water changes to err on the side of caution after reaching 88F.

Newest tank is 65 gal glass, and about 2.5’ off the ground on its stand. It is subject to full sunlight from a couple hours after sunrise til sunset (currently). I’m worried about when it actually gets hot out.
I do have an umbrella that I used for shade last summer, and can rearrange it throughout the day (if I’m home) to help control temps.

I try to keep the tropical fish at temps no higher than 84F and have found lower temps cause them more distress than higher temps. Right now the 65gal is at 88F. The fish and snails are eating & playing with gusto, and behaving normally still.
Granted, I have the thermostat cranked up since nights can dip 45-55F, I use the extra heat generated throughout the daylight to keep temps and 75F minimum thru the nights. However, summertime when outside temps are 85F+, in addition to the sun beating down on it, I’d like to know just how hot is too hot, and requires emergency water changes?

Stock:
Angelfish
Yo-yo loach
Rosy barb
SAE
Corydoras
Snails (mystery, ramshorn, Nerite, MTS, pond—love them in planted tanks!)

My garage tanks usually stay at around 87-88, over the summer with fans. I’ve seen no issues but it’s only for 3 -4 months. I’ve kept rift cichlids, bichir, various tetra and CA/SA cichlids out there

 

[DirtyPaws949]

My garage tanks usually stay at around 87-88, over the summer with fans. I’ve seen no issues but it’s only for 3 -4 months. I’ve kept rift cichlids, bichir, various tetra and CA/SA cichlids out there

I know angels usually like it a bit warmer, I think 84-86 is typical for them, end of the day so I just left the lids up to cool down a bit.

So far I don’t think I’ve had any fish die from being “too hot”, but I know I’ve lost some due to it being too cold (bichir jumped out into an unheated plastic tub, forgot to hook the heater back up one night after a water change and lost a catfish and something else when I found it next morning, and EVERYONE was struggling.. I felt awful).

Whats the temp it would get to that would be a “oh sh*t, I need to do a large water change NOW” temp?
90F+?

also, any higher temps would only be for several hours a day after the water heats back up and cools down, not like it’s 88F 24/7. Fluctuations are frowned upon, but I figure it’s gradual enough.Everyone seems to be doing fine with it so far ?

 

[Joshuakahan]

I know angels usually like it a bit warmer, I think 84-86 is typical for them, end of the day so I just left the lids up to cool down a bit.

So far I don’t think I’ve had any fish die from being “too hot”, but I know I’ve lost some due to it being too cold (bichir jumped out into an unheated plastic tub, forgot to hook the heater back up one night after a water change and lost a catfish and something else when I found it next morning, and EVERYONE was struggling.. I felt awful).

Whats the temp it would get to that would be a “oh sh*t, I need to do a large water change NOW” temp?
90F+?

also, any higher temps would only be for several hours a day after the water heats back up and cools down, not like it’s 88F 24/7. Fluctuations are frowned upon, but I figure it’s gradual enough.Everyone seems to be doing fine with it so far ?

I’d think 93 and up since the only issue I had was an Oscar in a qt and apparently the heater malfunctioned I noticed he wasn’t looking good and the thermometer read around 95

 

[DirtyPaws949]

I’d think 93 and up since the only issue I had was an Oscar in a qt and apparently the heater malfunctioned I noticed he wasn’t looking good and the thermometer read around 95

yeesh! Okay good to know. Thank you for sharing your experience. A few times last summer when I did the emergency changes it was 90-92F!
the fish seemed fine, they always eat like piggies though.
For large water changes I take out about 10- 20%, then run the hose and siphon simultaneously to avoid huge temp fluctuations while trying to correct the heat.

 

[Joshuakahan]

yeesh! Okay good to know. Thank you for sharing your experience. A few times last summer when I did the emergency changes it was 90-92F!
the fish seemed fine, they always eat like piggies though.
For large water changes I take out about 10- 20%, then run the hose and siphon simultaneously to avoid huge temp fluctuations while trying to correct the heat.

No problem
For my garage tanks I replace the glass tops with light defusers and run fans on them over the summer , I’m in Phoenix and it’s hot 24/7 for 3-4 months sometimes more and that keeps them in the 87-88 range, I have to fill them daily tho due to evaporation but I use the coldest water I can

 

[duanes]

When I lived in Wisconsin, the biggest problem I had with outdoor tanks, were wild swing temp fluctuations.
At noon a tank in full sun might jump up 88'F in July or August, but drop during cool nights to 66' F by 4 am.
I solved this by using a 1500 gal pond as a sump, being dug into the ground kept its temps more stable, and circuited the more stable cooler water, thru the tanks in the sun.

Here in Panama where temps are always high (and even though I keep only Panamanian species), my 180gal is under a patio roof that provides shade most of the day, so it remains fairly stable, and although the 125 it is connected to, gets full morning sun, the water running back and forth between the two tanks helps buffer temps. I also use terrestrial plants that provide shade (and nitrate reduction) and water lilies to help soak up direct sun.
BTW, Most Panamanian aquarists use chillers to help keep temps reasonable for more common tropical species.


Most of the time very extra warm water won't kill tropical fish outright, but it will shorten certain species life span.
So researching the fish chosen for warm water, outdoor tanks is important.
For common angelfish, 80'F is at the high end of their range (some of the wild type may be better suited to higher temps, as they share water with.
fish like Uaru and Discus that are good choices for warmer water tanks.
Alcolapia species from lake Natron are another good choice for high temp tanks.
Rosey barbs come from from Asia, places like Afganistan, and Pakistan the water temps get cool, hardly ever as high as 80'F.
And a lot depends on which species of Cory you keep, some from northern S America species appreciate warmer temps, than those from more temperate areas of South America.

 

[DirtyPaws949]

When I lived in Wisconsin, the biggest problem I had with outdoor tanks, were wild swing temp fluctuations.
At noon a tank in full sun might jump up 88'F in July or August, but drop during cool nights to 66' F by 4 am.
I solved this by using a 1500 gal pond as a sump, being dug into the ground kept its temps more stable, and circuited the more stable cooler water, thru the tanks in the sun.
View attachment 1448234
Here in Panama where temps are always high (and even though I keep only Panamanian species), my 180gal is under a patio roof that provides shade most of the day, so it remains fairly stable, and although the 125 it is connected to, gets full morning sun, the water running back and forth between the two tanks helps buffer temps. I also use terrestrial plants that provide shade (and nitrate reduction) and water lilies to help soak up direct sun.
BTW, Most Panamanian aquarists use chillers to help keep temps reasonable for more common tropical species.
View attachment 1448235
View attachment 1448236
Most of the time very extra warm water won't kill tropical fish outright, but it will shorten certain species life span.
So researching the fish chosen for warm water, outdoor tanks is important.
For common angelfish, 80'F is at the high end of their range (some of the wild type may be better suited to higher temps, as they share water with.
fish like Uaru and Discus that are good choices for warmer water tanks.
Alcolapia species from lake Natron are another good choice for high temp tanks.
Rosey barbs come from from Asia, places like Afganistan, and Pakistan the water temps get cool, hardly ever as high as 80'F.
And a lot depends on which species of Cory you keep, some from northern S America species appreciate warmer temps, than those from more temperate areas of South America.
View attachment 1448237

thank you for the very informative post! I had a 10gal and 5.5 gal tank in relatively the same spot at the 65gal last year, those were a pain to keep cool.
the 180gal is about 3-4 feet away from the 65gal on the right, then the 75gal and 20 gal are across from it about 4-5 ft. I wish I could figure out a way to get them all heated and filtered.
75gal gets a bunch of shade from the neighbors tree (this is all on my small side-patio haha, where I have the 4 tanks and a bunch of plastic bins with plants and a grow-bag garden watered with fish-water haha) and when I cover the surface with floating plants the sunlight doesn’t hit many of the sides there. I can replace the glass lids on the 65gal with floaters to help with heat from above
I am still out to get a 650 or 725 gal aquaculture tank for my large New World cichlids for the backyard, hoping late spring early summer... they’ve been waiting a while
If/ when that happens, I will likely move the 150gal they’re currently in outside where the 75gal is (across from the 65gal) and move the angels into that tank (with the old 75 gal as a sump/ convict tank) since the 150gal already has an overflow box and hole drilled.
I have way too many angels and they are too big for the 65gal. Unfortunately all 9 of them came with 2 aquariums I purchased (one by mistake, wrong dimensions were given) and I had to sell one of the tanks off. Both tanks were badly neglected when I broke them down and the fish were in bad shape. Ich, camallanus worms, mouth rot, fin rot... the poor koi male’s mouth was literally falling off and starting to eat into his face (now healed, but he’s now missing the upper flap of his mouth probably forever, one of the corydoras also had its face melting).

(he was biting at the glass at the same time I was taking the photo to show, either he’s bullying me for food or posing for you guys!)
I’m sure being forced to live in 60gal tank with a 13” red tilapia (previous owner) did not help their stress and immune system.
I had read higher temps activate the angelfish immune system (but does speed up metabolism and decrease longevity) but now that ich and rot is under control, I can probably bump it down some.
thank you for the temperature info on them.
corydoras currently in the 65gal are pandas, but I’m considering swapping them out for the sterbai/ false Julii from the 180gal (I have panda, sterbai, false Julii, albino, peppered, and a couple oddballs).

I will change the new maximum temps for my tanks to 80F and plan accordingly for weather, definitely the turn down the thermostat on the heater(s). Maybe a chiller would be my best option, since I rather enjoy how much the sunlight helps the plants. This might be a bit anthropomorphic, but I feel like natural sunlight also boosts fish (and critter) health and happiness, which is why I’m set on moving ALL my fish outside, despite the challenges of the elements.

The 180gal stock is
Buenos Aires tetras
Gold dust/panda mollies
Bettas
Guppies
Corydoras (above mentioned sp)
Dojo/ weather loaches
Old granny 3 spot gourami
Florida blue crays
Few random fish

75gal stock is
Convict cichlids
2 bichir (population control ?)
2 spotted Raphael cats (they’re hard to find locally, want 3-5)

 

[DirtyPaws949]

Just checked the thermostat on the 65gal heater and it’s set to 77. The lowest temp range on the dial reads 67F, but it looks like there’s a nub preventing it from going any lower than 77F