Topic: What is the best aquarium tank size for molly fish? All my fish are healthy thus far and getting used to their new surroundings. It’s been a good couple weeks of honest education, good preparation, trial and error, and learning as I go. Fish keeping isn’t just buying a bowl, throwing tap water in it, and throwing your fish inside. Need your help?

*Awarded Answer
Posted by Megan D: When we talk about the amount of fish to keep in a fish tank.. there is a lot of opinionated answers. I’m going to try and give you my best answer based on my decade of fishkeeping experience. Lets answer your question now.

Aquarium Tank Size for Molly Fish

The best tank size for a molly fish is a 10 gallon aquarium minimum. Mollies typically thrive best with 2-4 females per every 1 male. Figure on around 2-4 mollies as an ideal amount of molly fish to have for a 10g aquarium. I opted to getting a 20 gallon tank: not too small yet not too large for me to handle. You always want to have at least one gallon of water per inch of fish. Since mollies can grow to be 3 inches long, 6 mollies will be fine in 20 gallons of water.

 

Mollies are a tropical community type of fish and thus get along well with each other, platys, guppies, etc. When deciding to get a fish, you always want to triple check their compatibility chart with other types of fish as some can be more aggressive than others. Honestly, Pet Smart had their fish tanks labeled awesomely. On each tank, they explained what type of fish it was, what community it lived it, compatibility with other fish, how much plantation they enjoy, etc. It was a super good guide.

This is such an important fact when thinking about getting fish. For example, a simple goldfish can grow to be over 12 inches long. That’s a big fish!!! Having a fish with the potential to grow that large means you need to have a large tank right from the get go. Taking your child to the pet store, getting them 3 goldies, and throwing them in a bowl is the absolute worst thing you can do. You’re not providing them with enough space to grow, thrive, and have fun in. Odds are your goldfish will prematurely die from stress and be stunted from not being given the space to grow.

 

As a recent asker.. i have seen this picture and wasnt confident in my first time sexing and wanted help from people far more knowledgeable in the fish than me (especially when my guesses go against what i was sold the fish as). i know repeat questions are annoying, but i can tell you it helped me a lot to have my hunches verified and also was shown a live male fish. That helped me more than any drawn picture. so sorry if i annoyed anyone, thanks for the kind help of those who commented on my post. i googled for 3 days before i came to ask you guys.

Exactly exactly what I went through the exact same thing.  People were rude. I even explained I was somewhat experience, have a few years under my belt, but, it went against what my lfs said. Also I shared my thoughts and why. It’s behavior.  And just wanted to verify its sex. Either people were rude or actually shared their thoughts.  Funny thing was I had multiple comments going both ways. Damn fish can’t verify as any gender right now.

I just want to double check with people who have owned them longer than me. Is this fellow a boy? He and his other male companion are very ‘intimate’ so I always second guess myself. I do have fry in my tank but I believe they were from a different fish.

I am new to fish and to save for a long story, I am doing a fish in cycle. My dalmatian molly is suddenly sick. I didn a 50% water change this morning and added seachem prime. I am not sure if this is popeye or Viral Haemorrhagic Septicaemia. Thanks for any help.

I have a new molly that just hangs out at the bottom under a plant. Is there any reason for her to not want to leave her plant other than giving birth soon? I’m not sure if she’s pregnant or not but a little worried for her. The other new fish are very active.

There plenty hiding spaces got lots off plants etc and bogwood to hide behind had lots off fry over the last year but never like this.

It also looks like she has dropsy. It’s when a fish bloats and their scales pop out. I’ve heard an Epsom salt bath works but when mine had dropsy I used Pimafix

I’d vote against pimafix in your tank to but yes to an epsom salt bath. Something is definitely stressing her and causing her discomfort.

I’m so incredibly sad but one of our female Molly’s has swim bladder problem and is upside down struggling to move at all. HELP PLEASE! Water parameters are fine but I did realize for some reason water temp was only 74. I unplugged and plugged back in the heater and it kicked on now. I had to remove the sick molly as the others were picking in her. She is in bucket and I’m trying to keep water warm.

 

Aquarium Size for Aquarium Molly Fish?

• How long ago did you put the last fix to the water? Your filter may just be overtaxed and will get the cloudy out eventually.
• Over a week ago? When I initially got the tank all set up it sat for a few days and the water was crystal clear. I then got API tap water conditioner, put in the correct amount, and then the water went cloudy within a day of that conditioner cycling. It lasted like that for 3-4 days. I got it tested and they suggested stress coat (which is literally the same thing I put in with aloe Vera for the fish which didn’t make any sense because I had no fish yet). I let that cycle. Water cleared up just barely. Got water tested again and they were like “you’re good!” And so far my fish seem great. Filter has been running throughout this entire process.
• Okay, sounds like bacterial blossom then. Since your tank is relatively new no colonies have developed to clean the water yet. Takes a few months. If it’s still cloudy in a month then I’d probably look into getting a gravel vacuum.
• If anyone has advice on pregnant molly fish, I would greatly appreciate it. I have the mesh separation tank, but I don’t know when is the right time to place the pregnant fish in there. I don’t want to put her in too soon, however I have no idea how long she’s been pregnant. We bought her pregnant about 3 weeks ago. And throughout this week her belly had almost doubled in size.
• I have but I dont know how long she’s been pregnant and I have 2 other types of fish in the tank, and they would eat the babies so I need to keep them separate until there big enough to be with the rest of the fish.
• Put them in a smaller tank.
  I suck the babies out of my main tank with a turkey blaster and put them in a mini tank cause they don’t need much air circulation like the bigger ones
• Mollies actually have teeth! They’ll nibble almost anything they can.They are mainly vegetarians, but they like to have some protein based food added to their diet. (Like me!) Also.. they tend to chew and eat plants and vegetation in tank, but that’s because they are always hungry and they will do almost anything for food. Regardless of how regularly you feed them, they will still beg for more. (Same.) They are live bearers. They do not lay eggs and will reproduce 5-100 fry per pregnancy!