Mollies keep dying

MHorn

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I need help. We are new to fishkeeping, and my mollies keep dying. I have a 28-gallon tank with 2 cory catfish and some mollies. Originally I had 2 panda and 2 dalmatian adult mollies. Two of the mollies died and the fish store felt sorry for me and gave me a bunch of babies which ended up being 7 after they grew a little. They range from 1-2" right now. My other two adult mollies died and now a bigger baby died leaving me with 6 little ones. I keep taking my water in and the fish store says it's fine. One of my baby damnations seems to have a little red near her fin. Is this gill flukes or fin rot?? It's driving me insane, please help!


Pics:
- one is of the older panda mollie and the top looks opaque
- one is of the baby panda mollie that looks opaque
- the dalmatian mollie has something red at the base of her side fin
- the water came from the filter and there was muck at the bottom ( cleaned 2 weeks ago)

Notes:
- When the mollie adults were dying, they looked like they were losing their color or becoming transparent????
- I have tried a few ick solutions that were suggested by the fish store because we were shooting in the dark
- About a month ago when cleaning the
- I cleaned the gravel a few weeks ago (rinsing in water) thinking there are parasites in it
- Only mollies seem to be affected. I've had the cory cats for 6 months.
 

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Finn1231

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Dont know much about mollies, but a few important questions; how often do you do water changes? I also thought i saw a plastic plant, which they could have scraped themselves on. Do you have a heater for them? A filter? Do you dechlorinate the water? If you do all of this, maybe get a test kit. It could be problems with the water parameters and could come down to if the tank is properly cycled and clean.
 

Sgooosh

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Dont know much about mollies, but a few important questions; how often do you do water changes? I also thought i saw a plastic plant, which they could have scraped themselves on. Do you have a heater for them? A filter? Do you dechlorinate the water? If you do all of this, maybe get a test kit. It could be problems with the water parameters and could come down to if the tank is properly cycled and clean.
we need the exact params...
most likely bacterial fin rot, salt will help
 

Colin_T

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Hi and welcome to the forum :)

How long has the tank been set up for?
How often do you do water changes and how much do you change?
Do you gravel clean the substrate when you do a water change?
Do you dechlorinate the new water before adding it to the tank?

What sort of filter do you have?
How often and how do you clean the filter?
What is the ammonia, nitrite, nitrate and pH (in numbers)?

What is the GH (general hardness) and KH (carbonate hardness) of your water supply?
This information can usually be obtained from your water supply company's website or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg: ppm, dGH, or something else).

Mollies need water with a pH above 7.0 and a GH around or preferably above 250ppm.

Have you added anything new (fish, plants, wood, etc) to the tank in the 2 weeks before this started?
Do you add plant fertilisers, supplements or anything else to the tank?

Are there any other fishes in the tank besides the mollies and Corydoras?

Can you post pictures of all the fish from the side, not just the top?

What is in the glass in the picture?


---------------------
SALT
I would add some salt, see directions below. Then see how they go.

You can add rock salt (often sold as aquarium salt) or swimming pool salt to the aquarium at the dose rate of 1 heaped tablespoon per 20 litres of water. If there is no improvement after 48 hours you can double that dose rate so there is 2 heaped tablespoons of salt per 20 litres.

If you only have livebearers (guppies, platies, swordtails, mollies), goldfish or rainbowfish in the tank you can double that dose rate, so 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 (1-2 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.

If 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.
 

StevenF

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Aquariums do best when water is replaced about once a week. I don't know if you are doing this. but if not I would recommend you raplace 50% of the water once a week. Be sure to dechlorinate the new water before put it in the tank.

I would also recommend you get a good test kit. Somes water parameters can change very fast. it is helpful to be able to provide us with your nitrate, nitrite, Ammonia, GH (generals (hardness) KH (carbonate) levels are. Some pet shops don't know haw to interpret test results and may miss the obvious.
 
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MHorn

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Thanks for the responses. There were lots of questions asked, so I'll try to answer in one place.

When I have taken our water to the fish store, they always say it's ok. I have done this while each of the 4 adults was going downhill. Their deaths took about 2+ weeks. Before our water change scheduled for today, here are the results from a test strip kit.
  • total hardiness ppm- 500
  • chlorine ppm- 0
  • bromine ppm - .05
  • ph ppm - 8.4
  • alkalinity ppm - 180
  • cyanuric acid ppm- 30-50

Different test strip
  • Iron - after cleaning - 0
  • Copper - after cleaning - 0.5
  • Nitrate - after cleaning - 25
  • Nitrite - after cleaning - 0
  • General hardiness - after cleaning - 120
  • Free Chlorine - after cleaning - 0
  • Total Alkalinity - after cleaning - 120
  • Carbonate - after cleaning - 8.2

Answers:

We inherited the tank + decorations 10 months ago. The previous owners had angelfish, all of the plastic plants and didn't have an issue with them. We setup the tank and added the fish about a week later. Originally we were doing a 50% water change every 4 weeks. The adult mollies didn't start dying until we have had them for about 4-6 months. The only thing we added to the tank was an Aquaclear 50 filter (upgraded from a Topfin filter) and a Tetra Whisper air pump.

We have a heater and keep the water at 82 degrees. The filter is an Aquaclear 50. We do a 25% water change every 2-3 weeks and clean the filter. Every other water change, we take out all the decorations (except for the gravel) and clean them. When we add water for the water changes, we use a water conditioner.

Questions:
  • Could the air pump be causing the issue?
  • Please confirm that if we do the low dose salt fix for two weeks that it won't hurt the corys
  • Why would this issue only affect the mollies and not the corys?
 

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