Molly fry spinning, some getting popeye?

sgropp311

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Hi, i started off with about 80 molly fry from several mothers. They’re between 4 and 6 months old now. There’s only about 30 at this point and that number was pretty constant for a while but as soon as they hit about an inch long they start spiraling and some of them get popeye. I have no clue what’s going on. The other fish kept with them are fine and have been. This has been going on for about a month. I do biweekly water changes of about 40% because of the bioload. It’s also fry from both mothers doing this. It’s very gradual with only one dying a week but whatever this is has killed off about 15-20 fry now. Tried aquarium salt, parasite meds, fungal meds and bacterial meds. Parameters are perfect. Don’t know what’s going on.
 

Colin_T

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It's a protozoan or bacterial infection in the brain, usually protozoan.
It's normally caused by a dirty environment that allows the protozoans to multiply and infect the fish.

The easiest way to treat them is to clean up the tank and add salt.

When rearing large numbers of fish in small volumes of water, it's better to do 75-80% water changes and gravel cleans every day or two. Filters also need to be cleaned regularly to reduce the numbers of microscopic organisms in the water.

-------------------
Wipe the inside of the glass down with a clean fish sponge.

Do a 75% water change and gravel clean the substrate every day for 2 weeks. The water changes and gravel cleaning will reduce the number of disease organisms in the water and provide a cleaner environment for the fish to recover in. It also removes a lot of the gunk and this means any medication can work on treating the fish instead of being wasted killing the pathogens in the gunk.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Clean the filter if it hasn't been done in the last 2 weeks. However, if the filter is less than 6 weeks old, do not clean it. Wash the filter materials/ media in a bucket of tank water and re-use them. Tip the bucket of dirty water on the garden/ lawn. Cleaning the filter means less gunk and cleaner water with fewer pathogens.

Increase surface turbulence/ aeration to maximise the dissolved oxygen in the water.

Add some salt, (see directions below).

-------------------
SALT
You can add rock salt (often sold as aquarium salt), sea salt or swimming pool salt to the aquarium at the dose rate of 2 heaped tablespoon per 20 litres of water.

If you only have livebearers (guppies, platies, swordtails, mollies), goldfish or rainbowfish in the tank you would add 2 heaped tablespoons per 20 litres and if there is no improvement after 48 hours, then increase it so there is a total of 4 heaped tablespoons of salt per 20 litres.

Keep the salt level like this for at least 2 weeks but no longer than 4 weeks otherwise kidney damage can occur. Kidney damage is more likely to occur in fish from soft water (tetras, Corydoras, angelfish, Bettas & gouramis, loaches) that are exposed to high levels of salt for an extended period of time, and is not an issue with livebearers, rainbowfish or other salt tolerant species.

The salt will not affect the beneficial filter bacteria but the higher dose rate (4 heaped tablespoons per 20 litres) will affect some plants and some snails. The lower dose rate (2 heaped tablespoons per 20 litres) will not affect fish, plants, shrimp or snails.

After you use salt and the fish have recovered, you do a 10% water change each day for a week using only fresh water that has been dechlorinated. Then do a 20% water change each day for a week. Then you can do bigger water changes after that. This dilutes the salt out of the tank slowly so it doesn't harm the fish.

When you do water changes while using salt, you need to treat the new water with salt before adding it to the tank. This will keep the salt level stable in the tank and minimise stress on the fish.
 
OP
sgropp311

sgropp311

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Joined
Apr 24, 2021
Messages
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Location
Rochester NY
It's a protozoan or bacterial infection in the brain, usually protozoan.
It's normally caused by a dirty environment that allows the protozoans to multiply and infect the fish.

The easiest way to treat them is to clean up the tank and add salt.

When rearing large numbers of fish in small volumes of water, it's better to do 75-80% water changes and gravel cleans every day or two. Filters also need to be cleaned regularly to reduce the numbers of microscopic organisms in the water.

-------------------
Wipe the inside of the glass down with a clean fish sponge.

Do a 75% water change and gravel clean the substrate every day for 2 weeks. The water changes and gravel cleaning will reduce the number of disease organisms in the water and provide a cleaner environment for the fish to recover in. It also removes a lot of the gunk and this means any medication can work on treating the fish instead of being wasted killing the pathogens in the gunk.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Clean the filter if it hasn't been done in the last 2 weeks. However, if the filter is less than 6 weeks old, do not clean it. Wash the filter materials/ media in a bucket of tank water and re-use them. Tip the bucket of dirty water on the garden/ lawn. Cleaning the filter means less gunk and cleaner water with fewer pathogens.

Increase surface turbulence/ aeration to maximise the dissolved oxygen in the water.

Add some salt, (see directions below).

-------------------
SALT
You can add rock salt (often sold as aquarium salt), sea salt or swimming pool salt to the aquarium at the dose rate of 2 heaped tablespoon per 20 litres of water.

If you only have livebearers (guppies, platies, swordtails, mollies), goldfish or rainbowfish in the tank you would add 2 heaped tablespoons per 20 litres and if there is no improvement after 48 hours, then increase it so there is a total of 4 heaped tablespoons of salt per 20 litres.

Keep the salt level like this for at least 2 weeks but no longer than 4 weeks otherwise kidney damage can occur. Kidney damage is more likely to occur in fish from soft water (tetras, Corydoras, angelfish, Bettas & gouramis, loaches) that are exposed to high levels of salt for an extended period of time, and is not an issue with livebearers, rainbowfish or other salt tolerant species.

The salt will not affect the beneficial filter bacteria but the higher dose rate (4 heaped tablespoons per 20 litres) will affect some plants and some snails. The lower dose rate (2 heaped tablespoons per 20 litres) will not affect fish, plants, shrimp or snails.

After you use salt and the fish have recovered, you do a 10% water change each day for a week using only fresh water that has been dechlorinated. Then do a 20% water change each day for a week. Then you can do bigger water changes after that. This dilutes the salt out of the tank slowly so it doesn't harm the fish.

When you do water changes while using salt, you need to treat the new water with salt before adding it to the tank. This will keep the salt level stable in the tank and minimise stress on the fish.
see the issue is, i already do a 50% water change every other day. I gravel vac twice a week and dosed with bacterial and parasitic meds. The tank has salt in it, it’s brackish. I keep trying to update what i’m doing, but they keep dropping like flies.
 

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