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I recently set up a small home tropical fish tank with 4 Mollys. It’s the aqua one 47 eco style. 
I feel I haven’t been given too much uneducated mixed advice and it’s caused a few problems. 
during my first tank clean I removed the decorations and fake plants, cleaned out the gravel and replaced it, all unknown to me that I should have had a gravel cleaner and shouldn’t have scrubbed the ornaments. Woke up the next day to one Molly that had passed away, I was gutted and felt awful. I’ve been terrified to clean the tank again since, but have purchased a glass cleaner magnet got different ornaments, and got the gravel cleaner but am yet to use it. 
I worked out that I have 2 males and a female, I’m not sure what the first one that passed away was. I wasn’t told what the correct ratio would be and how many would actually be better to have total, just “4 would be fine do you want a mix of male and female or one or the other?” 
so I just got a mix. 
I now think the female is pregnant ( at a guess) and she has taken to abusing one of the males, to the point he is miserable and I think has fin rot. He hides and cowers away from her only appearing when I feed them. 
i have just done a treatment tonight with wunder tonic, and will do a water change and clean the gravel in a few days. 

what are my next steps?

Will the male survive?

is it best to remove him completely from the tank?  and just have the female and other male, who are both happy as Larry in each others company and are thick as thieves together.

Should I get more females and remove the imbalance? 

Not interested in getting abuse and snarky comments. I’ve had that already when asking at a fish specialist shop for advice and it’s put me off going back. 

Beginner mum here who is genuinely concerned and gotten a bit attached to these fish that I just got as a gift for my child who was desperate for a fish tank! 
only looking for genuine helpful advice so I don’t need to keep explaining where the fish have gone.. i feel bad enough. 

thank you 











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Hi there and sorry you are having trouble and didn't get good advice from your pet shop. Have you read about cycling an aquarium? This is very important. It is the biological process that makes the water safe for fish. The cycling would have started when you added the fish but when you scrubbed everything and replaced the gravel, it upset the cycle.

1. Do not add any more fish. The mollies will grow, or reproduce and your tank is not big enough for many more as mollies are a medium sized fish.

2. Get some live plants in there as this will help the nutrient balance correcting. It will also give the male somewhere to hide.

3. Look up all about cycling an aquarium. I always did it this way...set up the tank and make sure the temp has stabilised. For a 2ft (old measurements here from an old lady) tank I would add 4 hardy neon sized fish. After 1 month, if all was well, I would add another 4 of the same and repeat this process until stocking level had been reached. This naturally starts the process without adding ammonia or other chemicals to artificially start the cycle. For a 3ft tank I would start with 6 neon sized fish and so on.

4. A good ratio for mollies is 1 male for 2 or 3 females. A group of all males will be aggressive.

5 Your fella will be stressed and could recover on his own, without the addition of chemicals or tonics, if the cause of his stress is fixed - good water conditions and places to hide.

6. Do daily water changes of about 10 - 20% but don't clean anything in the tank, including the gravel, for at least 1 month to help correct the cycle.

Good luck and feel free to ask more questions ?

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Hi Caryl, 

thank you for this response and advice! 
unfortunately this poor guy isn’t getting any better. 
I cycled the tank correctly before I got the fish and ensured I had the water right he before introducing them. Each time I’ve gone in to the shops with the fish I’ve had water tested and all is well. Except him :( he can barely swim and generally just hovers wherever he lands and can only swim directly vertical to the surface to try and get food, and if anything in his way he gets caught in it. It’s so sad to see. 

I have done 2 rounds of adding the Wunder tonic and gently done a gravel clean and replaced half the water as instructed on the bottle after a few days. 

I feel it’s not environmental now, its stress induced from the female. As the female and other male are totally fine and she is continuing to abuse him especially when I feed them. So I don’t think he’s getting much food. 

I feel I need to isolate him, but is it best to do this in the tank? Or remove him completely? Being a tropical I would need a whole separate tank for him with his own heater etc, I’m not sure I can do that. 
Or is it best to take him away completely and back to where I got them to see if they can help him. 

At such a loss I’m so sad to see him so unwell :( 







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You are most likely correct in thinking it is just him and not water conditions or all the fish would be showing problems. This is not an unusual situation for him to be in and he has possibly been permanently damaged too.

Easiest way to separate him is to float him in the tank in a plastic container eg ice cream container. I sometimes pegged mine to the side so it didn't float around and get stuck under the water return in the days I used HOB (hang on the back) filters. Only give him enough water at first to stay upright. This allows him to rest easily on the bottom of the container. You will need to do partial water changes daily in the container. I used to use a turkey baster to do this as I had one on hand and it was less stressful to the fish. Easier to lift the container out, tip half the water out (without losing the fish down the drain) and top it up with tank water.

A 2L ice cream container is better than a clear one as he can't see out and she can't see in. Do note though - if you use a white container, the fish will turn very pale as they try to match their surroundings. A dark blue, or black, one would be better.

Feed him tiny amounts and fingers crossed he improves.

In the meantime, try and add more plants, live ones preferably, so he has plenty of places to hide. Out of sight, out of mind, works with fish. Water sprite or Indian fern (Ceratopteris) is good for this. Java fern (Microsorium pteropus) is very hardy and a good beginner's plant. It attaches itself to rocks or driftwood. Tie a few of the roots to a rock, or jam them into a split in the driftwood, and it will grow from there. No need to plant the roots into gravel. Both these plants reproduce by forming baby plants along the parent plant so you just pick them off and plant them. Sprite is also interesting as it will grow above the water surface and, when it does, its leaves look totally different!

Fish can damage themselves on fake plants, depending on whether they are plastic or silk stuff and live plants are better for both fish and aquarium nutrient balance.

Please let me know how you get on!

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