A Problem With Mollies

Hey guys! I've been stalking the forums for some time learning slowly that fish keeping is more difficult than it seems!

However, I am in college right now and they only let us have a 10 gallon. Initially I bought two mollies (a dalmation and a tequila something, it was orange and it looked cool) and an albino cory catfish.

I went to clean my tank for the first time, got all my fish out and dumped the water, rinsed the decorations and scooped up as much of the gravel as I could, cleaned all of it off dumped it back in the tank, filled it with water and used water conditioner. Long story short, shortly after I put my fish back in one of my mollies developed the shimmies and suddenly became very shy but my other molly was doing just fine so I didnt think much about it. Ultimately I lost the tequila molly and while the dalmation molly never was extremely active because she got bullied by the other molly, but now shes very lethargic and hides often.

I am concerned because I already lost a molly and I am thinking that it might be because she has no other molly to shoal with.

Currently in my tank I have 2 female fancy guppies, 2 albino cory catfish, and the dalmation molly.

I'm thinking about getting another molly but I'm not sure if it would over crowd the tank.

Note: I didnt originally have the two guppies or the second albino cory cat

Any help on what caused my molly to die, and suggestions as far as tank stocking will be much appreciated!

 

Is your tank cycled?

 

I just lost a molly too, and am dealing with a new tank, also. I'm sure the experts here can tell you what happened.

 

Is your tank cycled?

It should be, I've had it for a couple weeks now. But then again maybe, I washed all the good bacteria out when I cleaned the tank,

 

I think you need to review your cleaning the tank steps. There is no reason to fish the fish out, clean the gravel and whatnot. Cleaning the gravel likely contributed to your death of the fish. Gravel does carry beneficial bacteria, so when you remove it to wash it or replace it you do set the tank back, especially if the tank is still brand new.

What you should have done is replace about 50% of the water, refill, condition and walk away. That's it.

I would get the water tested to see where you are at and if the tank did restart it's cycle. If the parameters are off no fish, if they are good you should be able to put fish in.

 

I think you need to review your cleaning the tank steps. There is no reason to fish the fish out, clean the gravel and whatnot. Cleaning the gravel likely contributed to your death of the fish. Gravel does carry beneficial bacteria, so when you remove it to wash it or replace it you do set the tank back, especially if the tank is still brand new.

What you should have done is replace about 50% of the water, refill, condition and walk away. That's it.

I would get the water tested to see where you are at and if the tank did restart it's cycle. If the parameters are off no fish, if they are good you should be able to put fish in.

I agree. You probably shocked your mollies by taking them out and putting them in brand new water. Since you cleaned the gravel and decorations I don’t think your tank is cycled anymore. I would take your water to get tested or buy a water test kit (I like the API one). Your Nitrite should be 0, Ammonia 0 and Nitrate between 0-40ppm. If it was 40 it’s be time for a water change but I don’t think that’s your case so focus on the nitrite and ammonia. If you do have ammonia treat your tank water with Seachem Prime as it detoxifies ammonia for 24 hours. In the future I reccomend changing 20-25% of your water weekly to ensure you have a happy aquarium. I would also reccomend learning the gender of your Molly (you can post a picture here or find out online) and then when you go to the fish store make sure you buy the same gender. If not you’ll be overrun with babies and the 10 gallon can’t support the amount of fish fry you’ll have

 

I think you need to review your cleaning the tank steps. There is no reason to fish the fish out, clean the gravel and whatnot. Cleaning the gravel likely contributed to your death of the fish. Gravel does carry beneficial bacteria, so when you remove it to wash it or replace it you do set the tank back, especially if the tank is still brand new.

What you should have done is replace about 50% of the water, refill, condition and walk away. That's it.

I would get the water tested to see where you are at and if the tank did restart it's cycle. If the parameters are off no fish, if they are good you should be able to put fish in.

Now that I'm thinking about it, I did probably reset the cycle, I scooped out the gravel because when I first got my fish I over fed them and the food drifted to the bottom and the Corys didnt touch it so I scooped that out and now that you mention that it does carry beneficial bacteria I probably shouldn't have done that. In other cleaning videos I saw people with a gravel vacuum so I did my best to clean cause I figured I needed to
However, in my defense my other molly was fine so I was thinking that I had hurt the now dead one or it somehow got sick

 

I agree. You probably shocked your mollies by taking them out and putting them in brand new water. Since you cleaned the gravel and decorations I don’t think your tank is cycled anymore. I would take your water to get tested or buy a water test kit (I like the API one). Your Nitrite should be 0, Ammonia 0 and Nitrate between 0-40ppm. If it was 40 it’s be time for a water change but I don’t think that’s your case so focus on the nitrite and ammonia. If you do have ammonia treat your tank water with Seachem Prime as it detoxifies ammonia for 24 hours. In the future I reccomend changing 20-25% of your water weekly to ensure you have a happy aquarium. I would also reccomend learning the gender of your Molly (you can post a picture here or find out online) and then when you go to the fish store make sure you buy the same gender. If not you’ll be overrun with babies and the 10 gallon can’t support the amount of fish fry you’ll have

I think my mollie is a female, from the pics I've seen.

But do you think it's okay for me to get another? I've done some research and I'm actually over the 1 gallon per inch of fish rule. (I know it's not an exact measure, but I figured it's at least a ball park).

I'll get a pic of the molly I have left just to make sure its female

One of them is clearer than the other, but the other In my opinion is a better picture, if you can fight through the blurriness.

It is quite stressed because I took the hiding spots out of the tank because I couldn't get a good pic other wise

I don't want to freak out because it's doesn't look like shimmies but now it is staying in one spot and just kinda wobbling if that makes sense

 

I don't want to freak out because it's doesn't look like shimmies but now it is staying in one spot and just kinda wobbling if that makes sense

Do you have a heater in there?

 

Do you have a heater in there?

No, but the water temp. Is about 78, my room is pretty hot

 

I would not get another fish until you are sure your tank is cycle, because if it is not cycled your fish will most likely not survive, or get ammonia poisoned etc..

Another thing is that cory catfish should be kept in groups of 6 or more and a 10 gallon is very small for a group of 6 cory.

 

I would not get another fish until you are sure your tank is cycle, because if it is not cycled your fish will most likely not survive, or get ammonia poisoned etc..

Another thing is that cory catfish should be kept in groups of 6 or more and a 10 gallon is very small for a group of 6 cory.

I know.. if I could do it again I would devote my tank to one type rather than a community tank. It's just too small. But actually my corys are great. They are super active, and are always scavenging around for extra food And I haven't had any problems with them at all.

I know it's kind of a shot in the dark but is it possible my molly just really likes one of my decorations? And that's why it doesn't want to leave? It comes out to eat and isn't being territorial at all.

 

No, but the water temp. Is about 78, my room is pretty hot

Are you sure, do you have a thermometer in there? When I cycle tanks using mollies without heater they sit in the one spot and shiver. Without a heater the water temperature will fluctuate with the weather.

 

My younger cory is the most active, it's always swimming in almost a pattern in front of the tank glass, not susursusure if that means hes begging or not but its cute

Are you sure, do you have a thermometer in there? When I cycle tanks using mollies without heater they sit in the one spot and shiver. Without a heater the water temperature will fluctuate with the weather.

I bought the tank second hand and they have a sticker thermometer on the side of the glass, not the most accurate thing in the world but I'm a broke college kid and I can't afford a better one right now

 

I know.. if I could do it again I would devote my tank to one type rather than a community tank. It's just too small. But actually my corys are great. They are super active, and are always scavenging around for extra food And I haven't had any problems with them at all.

I know it's kind of a shot in the dark but is it possible my molly just really likes one of my decorations? And that's why it doesn't want to leave? It comes out to eat and isn't being territorial at all.

Yeah I think you should read a litte more into it. For Coris to really thrive and be happy they need be in groups. They are schooling fish just like tetras they feel secure and like to be in groups.

 

Yeah I think you should read a litte more into it. For Coris to really thrive and be happy they need be in groups. They are schooling fish just like tetras they feel secure and like to be in groups.

I wish I had, but I went into this thinking fish were easy and went off suggestions from a friend and the local petsmart

But I did and now I'm trying to make it work as best I can

 

I’d get a heater, if you have a constant temperature it wouldn’t be as stressed, it’s symptoms of shivering and staying still is cold.

 

I’d get a heater, if you have a constant temperature it wouldn’t be as stressed, it’s symptoms of shivering and staying still is cold.

Okay, any suggestions? Theres a petsmart locally but there is a local pet store about 20 miles away

I’d get a heater, if you have a constant temperature it wouldn’t be as stressed, it’s symptoms of shivering and staying still is cold.

Do you think that's what killed my other molly? Cold temperature from when I refilled the tank maybe? I noticed a temperature drop but it wasn't a lot

 

I don't want to freak out because it's doesn't look like shimmies but now it is staying in one spot and just kinda wobbling if that makes sense

Welcome to the wonderful world of fish keeping.

I have mollies and the good news is, they're tough fish. As long as you can keep the parameters in the safety zones for a fish in cycle, the dalmation should survive.

From my experience with mine here's my advice and reasons.

From you pictures, I'm really sure you have a female. The analfin of a male is thin and he keeps it close to the body. The females have the more circular fin and keep them extended.

Now for good news/bad news.

Dalmation females usually grow to be 5 inches in length. Mollies need to be kept as the only 1 of their gender or in groups of at least 3. You already are the main reason. Mollies establish a hierarchy within each gender and the dominant molly likes to show off who is boss. If you only have 2, the subordinate molly never gets a break from the alpha's business and will become stressed.

So, if you wanted more mollies you would need 2 more and a 10 gallon can not sustain 3 mollied ing one is a female dalmation. There just isn't enough swimming room and mollies are very very dirty fish.

Good news is that, although mollies are shoaling fish, they don't requires another molly to remain healthy. A molly can be kept alone without any harm to their health. So, your girl will be fine once you get your water stabilized and decrease her stress.

For her stress, I would recommend putting the hiding places back in. I would, also, suggest putting in tall plants, preferably live but fake if you can't do live. Mollies are mid to top level swimmers. They prefer to hide behind plants rather than in caves.

For stabilizing your tank:
Like I said, mollies are dirty fish, so its usually a good idea to modify your filter, any filter, to grow a larger bacteria colony inside. This serves 2 things - a larger bacteria colony will help keep the water healthy and is needed when dealing with a molly and having the majority of your bb in your filter protects the tank from having a mini-cycle when you clean. To get a bigger colony in you filter, add fluval biomedia or biosphere in the open part of your filter. Leave it alone except clean it once per week by swishing it in used tank water. Preferably add as much biomedia as your filter will take. I have 2 fluval biomedia packs in all my molly tanks.

It would be a good idea to get an apI master test kit especially if you're not sure you're cycled or if you are having to recycle. One of the best ways to k ow if something is wrong with your fish is to check the water parameters because water parameters are the easiest things to fix with water changes. Also, pretty much the first question you'll always be asked is 'what are your water parameters?'

For cleaning in the future, unless you have a major algae problem, the best way to clean a molly tank is a small tank vacuum. Vacuum the gravel and move it around once or twice a week. This will remove a bunch of the waste and remove water for a water change.

Good luck with your tank.

Oh and a fun thing to do with mollies - buy freeze dried blood worms, hold on in your fingers and lower it until it just touches the water. Most mollies will swim up and take it from your fingers without hesitation.

You'll, also, need to keep an eye on her for the next 6 monthes in case she's pregnant because you'll need to decide what to do with a fry and a female that's been in a tank with a male is more often than not pregnant. If she is pregnant, you'll be dealing with fry up to 6 monthes after the last time she was around a male. Fun fact about mollies, just because a molly has given birth, doesn't mean she's not still pregnant.

 

Do you think that's what killed my other molly? Cold temperature from when I refilled the tank maybe? I noticed a temperature drop but it wasn't a lot

It might have contributed to the issue. When adding water for a water change, make sure it's at least room temperature, preferably a little warm. What seeks slightly chilly to us when we're putting a finger in the water is a sudden cold shower enveloping the fish that's not much bigger than our fingers.

 

Welcome to the wonderful world of fish keeping.

I have mollies and the good news is, they're tough fish. As long as you can keep the parameters in the safety zones for a fish in cycle, the dalmation should survive.

From my experience with mine here's my advice and reasons.

From you pictures, I'm really sure you have a female. The analfin of a male is thin and he keeps it close to the body. The females have the more circular fin and keep them extended.

Now for good news/bad news.

Dalmation females usually grow to be 5 inches in length. Mollies need to be kept as the only 1 of their gender or in groups of at least 3. You already are the main reason. Mollies establish a hierarchy within each gender and the dominant molly likes to show off who is boss. If you only have 2, the subordinate molly never gets a break from the alpha's business and will become stressed.

So, if you wanted more mollies you would need 2 more and a 10 gallon can not sustain 3 mollied ing one is a female dalmation. There just isn't enough swimming room and mollies are very very dirty fish.

Good news is that, although mollies are shoaling fish, they don't requires another molly to remain healthy. A molly can be kept alone without any harm to their health. So, your girl will be fine once you get your water stabilized and decrease her stress.

For her stress, I would recommend putting the hiding places back in. I would, also, suggest putting in tall plants, preferably live but fake if you can't do live. Mollies are mid to top level swimmers. They prefer to hide behind plants rather than in caves.

For stabilizing your tank:
Like I said, mollies are dirty fish, so its usually a good idea to modify your filter, any filter, to grow a larger bacteria colony inside. This serves 2 things - a larger bacteria colony will help keep the water healthy and is needed when dealing with a molly and having the majority of your bb in your filter protects the tank from having a mini-cycle when you clean. To get a bigger colony in you filter, add fluval biomedia or biosphere in the open part of your filter. Leave it alone except clean it once per week by swishing it in used tank water. Preferably add as much biomedia as your filter will take. I have 2 fluval biomedia packs in all my molly tanks.

It would be a good idea to get an apI master test kit especially if you're not sure you're cycled or if you are having to recycle. One of the best ways to k ow if something is wrong with your fish is to check the water parameters because water parameters are the easiest things to fix with water changes. Also, pretty much the first question you'll always be asked is 'what are your water parameters?'

For cleaning in the future, unless you have a major algae problem, the best way to clean a molly tank is a small tank vacuum. Vacuum the gravel and move it around once or twice a week. This will remove a bunch of the waste and remove water for a water change.

Good luck with your tank.

Oh and a fun thing to do with mollies - buy freeze dried blood worms, hold on in your fingers and lower it until it just touches the water. Most mollies will swim up and take it from your fingers without hesitation.

You'll, also, need to keep an eye on her for the next 6 monthes in case she's pregnant because you'll need to decide what to do with a fry and a female that's been in a tank with a male is more often than not pregnant. If she is pregnant, you'll be dealing with fry up to 6 monthes after the last time she was around a male. Fun fact about mollies, just because a molly has given birth, doesn't mean she's not still pregnant.

With all the fish I have did I over stock? I didnt know mollies got that big. The pet store I went to assured me they only get three!

So now I've got one molly, two female fancy guppies, and two Corys.

Also, I don't have plants, but I've got a tall cabin on stilts thingy and a cave and lately shes been staying in the bottom of the cabin

 

With all the fish I have did I over stock? I didnt know mollies got that big. The pet store I went to assured me they only get three!

So now I've got one molly, two female fancy guppies, and two Corys.

You're probably a little overstocked but a modified filter and live plants will help with the issue.

Most mollies do stay around 3 inches but there are massive differences depending on gender and breed. For example a male black molly will only get about 2.5 to 3 inches while the female will be more 3.5 inches. Dalmatians, for some reason, are the largest breed of mollies I know of, thoug I saw a reference to giant mollies that are even larger by a breedwr that's working on a line of blue mollies.

With fish, it's important to look up the gender and specific species to find out the expected adult size because there are a lot of fish where one gender is half the size of the other.

For what you have now, make sure your filter is set up for maximum bb growth, add some live plants and caves for the cories and watch your water parameters. The fish's behavior and how stable your water parameters are is the best indication of your fish's health.

But, like I mentioned before is you'll need to watch out for fry because your tank can't handle more fish and mollies are built to breed...unfortunately, so are guppies and guppies and mollies can interbreed. So, that is something else to consider when making a decision about if you want to return any of your fish and/or what you'll need to do to maintain your tank.

 

I wish I had, but I went into this thinking fish were easy and went off suggestions from a friend and the local petsmart

But I did and now I'm trying to make it work as best I can

well you are here now so you are doing the right thing, trying to learn to make sure your fish are ok.

 

Hey everyone! It's been a couple weeks and I got everything yall said to get. My molly is doing much better now! She still hides a little bit (by hiding I mean not coming out till I feed her, and then going back to hiding all day), but shes doing much better! She seems to be a lot better!