Temperature fluctuations

[koty]

I read in O. Romer's book that some apistogramma species require seasonal and even daily temperature fluctuations. The lack of these, he claims, can compromise the immune system and more specifically cause hexamita. I am intrigued since it is the third case of hole in the head I have. I keep the temp constant at 27-28 °C. (I ruled out poor nutrition since I feed with live white worms, frozen blood worms, frozen adult artemia and tetra bits, and I have a massive filtration system with 50% weekly change, RO+ peat extract) Does any body here have any experience or input wether temprature shuold be managed?
Thanks
Koty

 

[Mike Wise]

Fish in the wild go through temperature changes every day by swimming from deep to shallow & sunny to shaded waters. Some, like those from the savanna regions tolerate fairly wide swings in temperature. All I can say is that I have never had hexamita problems in my fish room, which is centrally heated to keep the temperature stable.

It's hard to say what causes hexamita. Some claim nutrition, others water conditions, others stress. It's even possibe that it is due to a combination of factors, some that we don't usually check, like metals or other toxic compounds that find their way into our tanks.

 

[koty]

Regarding the temperature I was only quoting Romer.
I think that I can safely rule out toxic compounds such as metals or access trace elements since I regularly add home made peat extract.
I suspect that I might be overfeeding or giving unbalanced food (or both). Is it a good idea to give more artemia and less of the other foods that i mentioned? (This from the perspective of keeping the water cleaner)

 

[Mike Wise]

You would be surprised at the different kinds of pollutants that enter a tank for the air. Still, you probably are right. I assume you gravel clean every time you change water. Do you get much sediment from the gravel? If it consistantly comes up with a moderate amount of 'muck' every week, you might be overfeeding. Most of us overfeed our fish. This can lead to increased organics dissolved in the water, leading to rising electrical conductivity. Many fish are irritated by this, particularly the lateral line system on softwater fish. If your e.c. is high, I suggest cutting back on feeding & increasing water changes. This might help your problem. As for foods, I believe that variety is very important, as long as the fish eat the food. Even the best food is worthless if it is not eaten.

 

[koty]

Thanks for your reply,
My aq. is a 30 us gal, with a Rena XP3. And a tiny internal filter that blows water into an overturned 50 ml test-tube that collects CO2 from my yeast factory
I have quartz sand that is overturned frequently by:
A pair of M. Altispinosa (looking for food and breeding every three weeks)
Three adult thick coolie loaches.
5 cories (2 Rabauti and 3 wild unknown sp from Peru)
4 adult common ancistrus that is also massively digging as it lays eggs every three or so weeks)
The sand is perfectly clean (if I disturb or mix it, nothing comes out)
On top of the sand there are some organic matter that I clean occationally
and I have quite a lot of plants and all my wood and coconut halfs are thickly covered by green algae that I find nice and usfull for fry survival
The only food problem that I have is derived from the way the fish eat the tetra bits: they crush it to dust and a lot of it sinks to the bottom.
You are very right regarding the water especially that RO water are a powerful sink for solutes. A nice indication is that when I add peat extract the fish always react by enhanced color, breeding etc. This can be explained (although not exclusively) by the fact that the DOCs act as chealators of whatever sneaks to the water)
Here is a picture taken with a flesh (before adding the peat)