What could be wrong with my mollies?

Amelia
  • #1
Hi, about a week ago the temp in my tank dropped to 19°C due to the heater plug being flimsy (have changed the plug it was in). About a day later my black molly's tail started going limp and she started to rely more on her pectoral fins for swimming. Didn't really see any signs of distress. She stayed above the one filter and sort of tried to move in the current. Noticed that she was not well and dosed tank with salt. Not really a lot of salt though and it was dissolved in water before I poured it in. Did do 2 water changes in the meantime and cleaned gravel. Also reduced amount of salt in tank. I doubt whether this is ammonia/nitrite/nitrate poisoning as at least one of my other mollies and two guppies have started showing symptoms. From what I can figure out symptoms go as follow:
1) Either start with floating to the top once molly/guppy stops swimming and they really need to swim to reach bottom of tank. Or they start to swing side to side when swimming. My male molly and one of my male guppies showed both symptoms. Most of the other fishes only showed the swinging movement. Didn't notice it in the black molly but since she is a bit difficult to notice against the background I had, she could have showed it without me noticing. The floating to top thing stops after a few days.
2) some lethargy but not much. Seems to become more when they progress.
3) no loss of appetite. All fishes seem to be swimming to the top when they think I am going to feed them.
4) male molly has shown colour loss from tail forward and there might be lumps on him not sure because of his markings.
5) none of the affected fishes adult fishes has died but found 3 dead fry over 2 days. On the day I cleaned the tank (friday) and one yesterday. Tail fins where gone so the could have been a snack.
6) male molly can't stay completely still. He seems to move a bit every time he stays in one place. Almost like when you feel cold.

Not sure about size of my tank. Got it as a gift. It is a hex flat back and I suspect in the 160 to 200 litre range. Back measures at 90 cm, front at 60 cm, sides at 45 cm if measured in shape of rectangle. Sides measure at 30 cm and cut of corners measures at 21 cm. Tank is not cycled. I've seen ammonia poisoning in fish before and this does not look like it. Ammonia, nitrite, nitrate values are unknown. Did do a water change on Friday. Have two filters in tank not sure which kind. Water temperature is at 25°C and there is an air stone in the tank. Both filters also give air bubbles. Tank has been running for almost a year now with guppies and I added the mollies about three weeks ago. Destroyed the nitrogen cycle by accident just after that.

Any ideas about what this could be?

Sorry about the lengthy post but figured if I'm going to ask I might do it properly.
 

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Aquaphobia
  • #2
What are your current parameters? They are most important. If you can't get a test kit can you take samples of your tap water and tank water to the LPS and have them test for you? Be sure to write down the numbers! Never take their word for it that the results are "fine".

How long ago did you "destroy" the nitrogen cycle and how did you know you had? How did it happen?

What is the current temperature of the tank?

It could be that the cycle is in the middle of re-establishing itself and you could have elevated nitrites or both ammonia and nitrites. Even if neither the stress of what they've been through could have impacted their immune systems and left them open to opportunistic diseases.

What's your water change schedule? How much and how often?

We really need to know those parameters so the sooner you can get them the better!

Welcome to the forum! Hopefully someone here can help you
 

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Amelia
  • Thread Starter
  • #3
Thank you for replying. I might be able to get a test kit tomorrow (also need to go buy aquarium salt).
Destroyed the nitrogen cycle about 4 weeks ago because I cleaned the filter in tap water. (Oops. Realised the mistake after some research). Switched to rinsing it in old water from the fish tank when I clean.
Itry to clean the tank about once a week and do a water change then. I've added another filter in as well about 3 weeks ago. I also did a water change today so that totals the water changes between last week Friday and this past Friday to 3 changes.
Current temp is at about 25°C.
I moved the two mollies I know for sure are ill to a QT tank. And the male guppy who showed signs are missing.
 
Aquaphobia
  • #4
That's good, post the results as soon as you can!

I would skip the salt, it's not needed.

How much water do you change each time?

Do you use a water conditioner? What kind? Do you dose for the entire tank?
 
FeederGuppies
  • #5
Welcome to fish lore!

I think it might be ammonia poisoning, as mollies and guppies produce a lot of waste for their size.

Most mollies can grow to 4 inches long, so it depends on what size tank you have if they will be comfortable.

I would suggest only having all male/ all female live-bearers, because they breed like CRAZY. They might over whelm your tank, as mollies and guppies can have 20-30 babies EVERY month.
 
Amelia
  • Thread Starter
  • #6
I do use water conditioner. It's called Tetra Aquasafe. I do about a 25% water change as an estimate could be more. Definitely not half because that is way to much work with the size beaker I have available to use. Not sure what is meant by dosing entire tank, Aquaphobia, if you mean dosing with the AquaSafe, then I dose more or less for the amount of water I add.
FeederGuppies I got the guppies because my cousin said she knows someone who bought a few for their tank and then the guppies bred and now the tank looks beautiful (other people's tank, mine still needs to get there) . But I got tired of a species only tank hence the mollies. Figured they could breed and eat each other's fry (sounds a bit cruel now).
 

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Amelia
  • Thread Starter
  • #7
Thanks for the welcomes.
 
Aquaphobia
  • #8
With high bioload fish like mollies you're probably going to want to do much larger water changes than 25%. Also with the cycle supposedly being interrupted you'll need to be dosing for the whole tank volume to protect the fish from toxins!

AquaSafe is good but I would recommend getting Prime instead. It's more concentrated so a bottle lasts a lot longer

Here's a calculator so you can figure out the exact volume of your tank:
 
Amelia
  • Thread Starter
  • #9
Thanks for the advice.
 
FeederGuppies
  • #10
I thought that if I got guppies I would have no problems with over populating. Then my guppies had more and more fry...... Now I have a female guppy tank and a male guppy tank, lol.

I also starting realizing it was a little cruel to have a lot of the fry get eaten, but I guess I'm just a softy, lol.

Most of the fry born to guppies are females, so you will have a tank 2 thirds full of female guppies.

What size tank is it?
 
Amelia
  • Thread Starter
  • #11
172 litre, or a 45 gallon I think. Haha, I'm almost to scared to say that I leave them in. It sounds cruel but they do have hiding space.
 

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