NanDiscus
02-11-2012, 10:35 AM
A friend of mine -a dedicated and so far quite successful discus hobbyist- phoned me this morning and told the following story...
(A little background story first. My friend has a mid-sized hatchery with 6 breeding cubes of the bigger size, bare bottom, around 75 gals each with built-in chamber filters, all identical in every tank filled with filter wool, sponge cubes and ribbed plastic rings. Identical water paramers in every tank, identical w/c regime with water from his 1000gal reservoir, one pair in each cube. The hatchery has been running like this for over a year now, putting out thousands of marketable size babies, all healthy and growing like mould in a winecellar.
There are a few mid-sized grow-out tanks, another rack with 12x55 gallons in the front room (a part of Hans's old racks from the Dutch era) and a 125 gal community tank for resting pairs. The set-up has been keeping my friend busy and happy until the very recent times.)
The events of these very recent times he explained to me as follows.:
Imagine you have 4 tanks, let's call them A, B, C, and D. Each tank has a pair of experienced and very successful breeders, all big and fat and happy, and all on a spawning cycle again, laying eggs every 7-10 days. The last few times they laid eggs roughly at the same time, with no more than maybe a day or two between the first and last bunch of eggs. Here's what happened.:
Tank A: None of the eggs hatched, they all when opaque white after 24 hrs, no fungus to be seen at all.
Tank B: None of the eggs hatched either, but the entire lot looks like a furry animal, all covered in fungus.
Tank C: A few eggs hatched successfully, but the hatch rate is was still well under 10%. The unhatched eggs were fungussed.
Tank D: With the exception of a few eggs, all of them hatched, the rate was well over 95%, the unhatched eggs went white, but with no fungus visible.
One of the pairs in one of the cubes and a new pair in the orgy tank both laid eggs a few days ago on breeding cones. The cones were removed from the tanks and placed in a completely empty and fresh 25gal tank filled with water from the reservoir, with nothing but an airstone and a heater in it. The wait began and the results were surprising to say the least. Both batches of eggs hatched at a very high rate, close to 99%, the unhatched ones went white, but that's it. The wigglers look fine, my friend does 20% w/c's every day and it's roughly a day before they all go free-swimming.
The questions are:
-Why on earth is he experiencing so very different and random hatching rates in the breeding tanks with totally random appearances of egg fungus alongside?
-Why is it that the eggs don't hatch in the breeding tanks, but hatch very well in 'raw' water?
-What may be in the filters that can inhibit the development of the fertilised eggs?
-What other things do you all think he should be looking for that should be eliminated from the tanks?
The general water conditions are ~50ppm, pH between 6.5-6.8, NO2:0, NO3: under 20ppm constantly.
Any input would be greatly appreciated!
Nandi
(A little background story first. My friend has a mid-sized hatchery with 6 breeding cubes of the bigger size, bare bottom, around 75 gals each with built-in chamber filters, all identical in every tank filled with filter wool, sponge cubes and ribbed plastic rings. Identical water paramers in every tank, identical w/c regime with water from his 1000gal reservoir, one pair in each cube. The hatchery has been running like this for over a year now, putting out thousands of marketable size babies, all healthy and growing like mould in a winecellar.
There are a few mid-sized grow-out tanks, another rack with 12x55 gallons in the front room (a part of Hans's old racks from the Dutch era) and a 125 gal community tank for resting pairs. The set-up has been keeping my friend busy and happy until the very recent times.)
The events of these very recent times he explained to me as follows.:
Imagine you have 4 tanks, let's call them A, B, C, and D. Each tank has a pair of experienced and very successful breeders, all big and fat and happy, and all on a spawning cycle again, laying eggs every 7-10 days. The last few times they laid eggs roughly at the same time, with no more than maybe a day or two between the first and last bunch of eggs. Here's what happened.:
Tank A: None of the eggs hatched, they all when opaque white after 24 hrs, no fungus to be seen at all.
Tank B: None of the eggs hatched either, but the entire lot looks like a furry animal, all covered in fungus.
Tank C: A few eggs hatched successfully, but the hatch rate is was still well under 10%. The unhatched eggs were fungussed.
Tank D: With the exception of a few eggs, all of them hatched, the rate was well over 95%, the unhatched eggs went white, but with no fungus visible.
One of the pairs in one of the cubes and a new pair in the orgy tank both laid eggs a few days ago on breeding cones. The cones were removed from the tanks and placed in a completely empty and fresh 25gal tank filled with water from the reservoir, with nothing but an airstone and a heater in it. The wait began and the results were surprising to say the least. Both batches of eggs hatched at a very high rate, close to 99%, the unhatched ones went white, but that's it. The wigglers look fine, my friend does 20% w/c's every day and it's roughly a day before they all go free-swimming.
The questions are:
-Why on earth is he experiencing so very different and random hatching rates in the breeding tanks with totally random appearances of egg fungus alongside?
-Why is it that the eggs don't hatch in the breeding tanks, but hatch very well in 'raw' water?
-What may be in the filters that can inhibit the development of the fertilised eggs?
-What other things do you all think he should be looking for that should be eliminated from the tanks?
The general water conditions are ~50ppm, pH between 6.5-6.8, NO2:0, NO3: under 20ppm constantly.
Any input would be greatly appreciated!
Nandi