Ideal conditions for a Molly fry tank

[Kyra]

I got my pregnant Dalmation Molly which I had in my main tank for around 3 weeks before it gave birth (the only other fish in the tank were two male guppies), and it had 23 fry. The other fish were perfectly fine, but the fry died off the same night that they were born, and I was not sure why. It was a 20 gallon tank, 78F with no chlorinated water or cycling/dealgaeing chemicals added at all, a carbonated pocket filter and a small airstone added.

After owning fish for a few years in that tank, when the Female guppies I bred in the tank had fry, they all survived naturally, but whenever a Molly would have fry they would just die the same night they are born.

I have been thinking instead of letting the Molly breed her fry in a breeder net-box, I was going to separate them into their own tank to make sure that the only bacteria the fry are involved with is their mothers and their own, but I am not sure about if this would work or not.

Is there any specific things I need to have in the tank to insure the survival of the Molly fry? It's sad to see all of the little fry get born, swim into the plants to hide or sit at the bottom of the net, and then a day later be floating around the tank dead.

 

[Thyra]

It sounds like you had the molly in the breeder net box when she gave birth, but the guppies were in the tank when they gave birth - is that correct? I would put some plastic grass mats in the bottom of your tank and let nature take its course. You didn't say what your water tested and that is critical for fry - zero ammonia and nitrite and about 20ppm nitrates.

 

[OrangeCones]

I have no idea who invented the 'breeder net' to be a place for fry to be born in.

Fry at first do not have a neutral boyancy and must swim constantly or sink to the bottom. This is largely due to a yolk sack still carried with the fry. They are simply weighed down by it initially.

When fry sink to the bottom of the 'breeder net' other fish in the tank will peck at them thru the net. This often causes them physical injury, including death, as the fish eat small sections out of the fry as they rest on the bottom. If they are not pecked to death, they are often stressed, having to stay in constant motion or be eaten. The fry have little energy reserves and this can literally starve them very quickly, as they use up all of their energy to keep away from the pecking adults.

If you want the molly fry to survive, placing the mother in another (cycled) aquarium prior to birth is ideal. Otherwise, providing lots of cover in the form of decorations, rocks, large gravel, and plants (real or artificial) will help the survival rate.

 

[Kyra]

I have no idea who invented the 'breeder net' to be a place for fry to be born in.

Fry at first do not have a neutral boyancy and must swim constantly or sink to the bottom. This is largely due to a yolk sack still carried with the fry. They are simply weighed down by it initially.

When fry sink to the bottom of the 'breeder net' other fish in the tank will peck at them thru the net. This often causes them physical injury, including death, as the fish eat small sections out of the fry as they rest on the bottom. If they are not pecked to death, they are often stressed, having to stay in constant motion or be eaten. The fry have little energy reserves and this can literally starve them very quickly, as they use up all of their energy to keep away from the pecking adults.

If you want the molly fry to survive, placing the mother in another (cycled) aquarium prior to birth is ideal. Otherwise, providing lots of cover in the form of decorations, rocks, large gravel, and plants (real or artificial) will help the survival rate.

I never thought about that. Perhaps the guppies are just pecking at the Mollies and they are dying off. I never bothered putting the Guppies in the tank because all of the fry were left alone, due to the fact that the males never swam to the bottom to bug them and the other females generally stayed in the corners of their own tank. The only one who bothered the fry was the Molly.

You didn't say what your water tested and that is critical for fry - zero ammonia and nitrite and about 20ppm nitrates.

Is there anything I can do for this? Ammonia removal products or pmm nitrate balancers/modifiers?

 

[Thyra]

Do you have a liquid test kit so you can test your water? You will need frequent water changes to get the ammonia and nitrite to zero. I have never used any chemicals so I am unable to advise on that matter or even if it is a good idea.

 

[Kyra]

They have Ammonia removal kits at my pet store but I was wondering if there were other methods, or manual methods of doing it that are either better, or quicker. Will the Ammonia ever come back after removing it, and if so, how long will it take?

Also, how many days do you set out 5 gallons of Tap water before the Chlorine in it dissolves or goes away? I have heard rumors that it takes 1-2 days for a bucket of Tap water to lose all of the chlorine in it and be safe for fish, but I am not sure. So far my fish have been fine, but I decided to use dechlorinator instead.

 

[Thyra]

If you are using dechlorinator as directed the water should be ready for use immediately. (I have well water, but that is what others do) The ammonia comes back because it is excreted daily from your fish. You would do well to read the "Stickies" at the beginning of this forum - I think that would be a big help. Do you know what your exact readings for ammonia, nitrite and nitrate are right now? If you have any ammonia or nitrite, the best way is to replace at least 50% of the water. You may have to do this daily to get it normal while the good bacteria build up. The good bacteria thrive on the ammonia & nitrite and turn it into nitrate which then you maintain at about 20ppm by again doing water changes, but once its stable you will only have to do it about once a week and probably more like 30%. (Consider this a simply explanation, Ok? lol)

 

[KcMopar]

Also, how many days do you set out 5 gallons of Tap water before the Chlorine in it dissolves or goes away? I have heard rumors that it takes 1-2 days for a bucket of Tap water to lose all of the chlorine in it and be safe for fish, but I am not sure. So far my fish have been fine, but I decided to use dechlorinator instead.

If left in the sun outside a 5G bucket will lose the chlorine from tap water in 2-5 hours. Many city water company's do not use chlorine any longer, most have switched to chloramine. Chloramine is a chlorine molecule with ammonia added to it and is much harder to break down.