Temperature Drop expericences

[davidru]

I often read that temperature drops are harmful for fish and probably cause disease. I had some african cichlids for 3 years and I always did large water changes with water 2 - 3 degrees celcius lower than the tanks temperature. I never had any problems after the water changes. Ive also read advice of making this type of low-temp water changes to induce corydoras into spawning.

What are your experiences with this type of temperature drops?

 

[125gJoe]

Abrupt changes of say around 5 or more degrees will stress the fish. I hope most have thermometers to check the water when doing water changes.

 

[aquariumfishguy]

Unless I am changing water on a larger sized aquarium, in which case I would use a python, I get my water right from my bathtub. I stick a thermometer under the water and when its just about right, I start filling them buckets up! It works really well for me.

 

[JSchmidt]

I remember reading a book by one of the respected cichlid experts... maybe Loiselle... who regularly saw african cichlids spending long amounts of time on either side of a thermocline that separated waters that were 10-12 degrees F apart. He reported seeing no sign the change in temp stressed or bothered the fish whatsoever.

When I do changes in my office tank (where I cannot age water) the temp regularly drops 7 or 8 degrees. I've not seen any illness following these changes, or any signs of distress in the fish. On the contrary, I see the typical friskiness in fish that are in cleaner water.

What sorts of distress has anyone witnessed from temp changes more than a couple of degrees?

Jim

 

[TKOS]

Temperature change will not cause ilnnes. At worst it may lead to stress which will weaken a fish and make it more susceptable to illness. Same thing with people going out in the winter without a hat on. The cold does not give you a cold, but can weaken your immune system and make you ability to catch a cold from another person that much better.

I do very cool water changes in my white cloud/ cory tank. The cold water makes the white clouds dance and show off. The cories start to breed.

 

[aquariumfishguy]

What happens with extreme water temp differences is that (like others have said) it weakens the fish’s immune system to a point where any little issue that should arise could virtually spell disaster. Ick is one illness off the top of my head, which loves to attack a weak fish, and since the parasite is always among our fish in the water, your fish are bound to get it sooner or later, especially with a 7-10 degree temp change.

 

[125gJoe]

Originally posted by TKOS
Temperature change will not cause ilnnes. At worst it may lead to stress which will weaken a fish and make it more susceptable to illness.......

Exactly.

About "thermoclines".... It would be some experiment to try and get a thermocline going. Try and picture the size of that aquarium!

 

[JSchmidt]

I remain skeptical. At the very least, I think the species of fish and their general health are probably equally important factors.

The only behavior I've noticed in my fish (not uncommon, from what I've read) is a increased likelihood of breeding when doing a water change with cooler water.

Part of what I don't understand, on a physiological level, is how exposure to cool water is supposed to weaken the fishes' immune system. For example, exposure in humans to cold weather per se isn't what causes colds to become more common in winter, it's dry air reducing mucus protection against infection, coupled with being in closer quarters with others breathing recycled air, touching infected surfaces, etc.

Jim

 

[125gJoe]

Just a side note on thermoclines...

Fish actually 'choose' (instinctively) whether or not they want to go into the temperature change. With aquarium water changes, the fish have no 'choice' but to deal with whatever temperature there keeper decides to give them.

The point is, in nature abrupt water changes occur. With small ecosystems like aquariums, temperature control should be maintained.

 

[anonapersona]

Discus in low temps

I had a problem with a heater in a baby discus tank that allowed the temp to drop from 88 to 80. The discus ate far less than normal (higher temps stimulate metabolism) and that rich meaty food was left in the tank too long (possibly to attract bad bacteria or to host flukes development).

They developed white stringy poo and started scratching as if they had flukes of some sort. All fish were lethargic and darkly hanging in the corners. They would rush to food, then turn and swim away, only 8 or 23 were seen to eat, even after the temp was returned to normal. Tanks gets 50% daily water changes, siphons 3x/day.

Treated with epsom salts to try to expell the bacteria, then a shotgun medication to control possible Ich or bacteria.

yeah, discus are not the "normal" fish, but may ilustrate the extremes of what happens to fish in temp drops.