Agassizii infertility?

[Hellfishguy]

Back in June I acquired a young pair of Apistogramma agassizii Blue Flame. Since then, they've grown into spectacular specimens, but so far no fry. The female shows brood care behavior but abandons the cave after a few days. On two occasions what appear to be fungused eggs have shown up outside the cave. Are the eggs being fertilized or is the female still too inexperienced to care for them properly?

 

[anewbie]

Water condition? Could your water be too hard? What is kh/gh/tds ?

 

[Hellfishguy]

Water condition? Could your water be too hard? What is kh/gh/tds ?

My tap water is very soft - 31 ppm TDS. I've bred many species of Apistogramma without encountering this problem. The only similar case was a pair of A. macmaster which never produced fry, former inhabitants of the same tank the agassizii are living in now. This tank, unlike any of my others, is densly planted with Java ferns. Could the plants be releasing enough toxins to affect the eggs but not the fish?

 

[MacZ]

As we're dealing with a domestic strain that (at least here where I live) has a reputation for bad stock... I would not be surprised if the fish are not producing viable offspring in the first place.

 

[hongyj]

My tap water is very soft - 31 ppm TDS. I've bred many species of Apistogramma without encountering this problem. The only similar case was a pair of A. macmaster which never produced fry, former inhabitants of the same tank the agassizii are living in now. This tank, unlike any of my others, is densly planted with Java ferns. Could the plants be releasing enough toxins to affect the eggs but not the fish?

Plants don't really affect the eggs and I would argue are beneficial. Agassizii, though many are domestic strains, require very soft water or the eggs seem to calcify and not hatch leading them to just rot. Java fern would take away from the nitrates and are beneficial to the tank ecosystem so don't worry about it. Try reducing the water hardness to around 0-10ppm tds. TDS doesn't necessarily measure kH either, which is what affects the hatch rate of certain species. In some tanks, it's difficult to reduce tds that much evne with water changes with RO water so I would recommend placing the fish in a breeding 10 gallon with some sand at the bottom, the cave, some cover, and a line of sight break except the water is entirely RO water. The tank ofcourse should be cycled.

 

[Aquaticloch]

Agassizii, though many are domestic strains, require very soft water or the eggs seem to calcify and not hatch leading them to just rot. Java fern would take away from the nitrates and are beneficial to the tank ecosystem so don't worry about it. Try reducing the water hardness to around 0-10ppm tds. TDS doesn't necessarily measure kH either, which is what affects the hatch rate of certain species. In some tanks, it's difficult to reduce tds that much evne with water changes with RO water so I would recommend placing the fish in a breeding 10 gallon with some sand at the bottom, the cave, some cover, and a line of sight break except the water is entirely RO water.

I would generally disagree with what you said here, Agaaaizii are and have been domesticated for dozens of generations and decades of time, such as this morph shown on this post. After so long, adapting to common conditions kept in aquaria they do not still have the same amount of calcification you'd see with wild fish. TDS of 0-10ppm is extremely low. There are very few wild species that need that low to breed and they are absolutely blackwater fishes, which in this case these agassizi are not. KH also is not the only variable affecting hatch rate, and thats a very broad statement, KH also basically dictates the size of pH swings, lower kh resulting in a pH which can change more rapidly.

10 gallons for agassizi breeding should not be recommended at all. Agassizi are a large species, and are known to be quite aggressive and hence should be kept and bred in 20 gallons (78 litres) minimum.

Lochlan

 

[hongyj]

TDS of 0-10ppm is extremely low. There are very few wild species that need that low to breed and they are absolutely blackwater fishes, which in this case these agassizi are not. KH also is not the only variable affecting hatch rate, and thats a very broad statement, KH also basically dictates the size of pH swings, lower kh resulting in a pH which can change more rapidly.

Though kH is necessary for preventing pH crashes, apistos enjoy low pH. I've heard from other breeders that they've had to make their ph around 6.4 and reduce their hardness to around 10ppm.

10 gallons for agassizi breeding should not be recommended at all. Agassizi are a large species, and are known to be quite aggressive and hence should be kept and bred in 20 gallons (78 litres) minimum.

I've kept agassizii in densely planted 10 gallon tanks usually with proliferating java fern, java moss, rocks and driftwood along with forests of stem plants and they seem to do just fine.

 

[MacZ]

What the...?

- KH is ONE buffer system we can choose to use, and it is characterized by only buffering up. Means higher KH = higher pH. With every time you cut KH in half pH drops by 0.3 points. At KH 0 there is no buffer capacity whatsoever, after that the pH drops in a linear fashion with the addition/accumulation of H+.
- KH is also part of a. GH and b. TDS. Whenever you measure one of the latter two KH is included, no question. Do we get the number that way? No. Why do we measure TDS? Because KH and GH are both below detection in such soft water.
- A TDS reading of around 30 mg/l is as low as you can get in a fishtank. To get lower you need to add chemical filtration (DI, AC) to your normal day-to-day filter system.

Rolling back, if you go that low in your TDS you usually have to use humic substances as a buffer system, which buffer in the pH-range of 4-6 and keep it from going lower.