Upgrading to Larger Tank

[Sprank1]

I have a 10 gallon with 4 Mollies and 1 Male Betta. They all get along great, but I have been told that a 10 gallon tank is too small. I am planning on getting a 20L Gallon tank and moving them to that.

My questions:

How do I go about moving everything from the old tank to the new one? Unfortunately, the new tank has to go in the same spot as the old one, so I don't have the option of having both tanks run simulatneously. Any suggestions will be greatly appreciated.

Also - are 4 mollies (They are pretty small right now) and 1 male betta a good amount for a 20 gallon tank? Can I add anything else or is that a full load for that size tank? If I can add anything I would appreciate suggestions.

Thanks for everything and I want to say that these forums have been very helpful - very glad I found them.

[odobenus]

Greetings and salutations!

I would suggest getting a bucket (for use only with your aquarium), filling the bucket with water from your tank, and moving the fish into the bucket for the remainder of the switch. Then you could drain enough water from the 10 gal to be able to move it to a different spot. Set up the new tank, move the gravel (if you have a gravel substrate) and decorations to the 20 gal and fill it most of the way with water. Move your heater and filter over, and start them up. If you did a good job of matching the temp of the new water to the temp of the old water you should be able to move the fish from the bucket into your new tank.

The biological filter lives in your filter and gravel, so if you move those over you should avoid a cycle. I would test the water every other day or so for a while, until you are sure that you aren't experiencing a mini cycle.

If you are going to be using a new filter, I would just run the new and old filters together on the 20 gal. That will give the bacteria from the old filter time to colonize the new filter.

good luck!

(and hopefully someone will chime in if I've forgotten anything)

[mrcrazypants05]

I'm not entirely sure that 20 gallons would be enough. Depending on the type of molly they are. Atleast thats just what I've heard...

[oxymoron]

You could always just move the mollies to the 20 and leave the betta in the 10 by himself.

Max size on a molly is 4-5" so 4 in a 20 should work out well, plus if they are by themselves you could make it a brackish tank.

[Sprank1]

Thanks for the replies so far. From the information at the fish store, the mollies are only supposed to be about 2 to 3 inches when full grown. They are 2 gold mollies and 2 small dalmation mollies - They are about 1 inch long at the moment. If they only get to be about 3 inches then I figured that 4 of them would be ok in a 20 gallon tank. If they get bigger I will have to think about a second tank or a bigger tank.

Hopefully they will fit as I only have room for a 20 and I don't really want to give up any of my fish.

[mrcrazypants05]

I beleive a 29 gallon has the same footprint... its just higher. I've heard that mollies like a lot of swimming space, but I guess in a 20 gallon by themselves without the betta they would have plenty of room. Do you know if they are females or males? How long have you had them and how are they acting with each other? Just wondering.

[TomK2]

You may have some transient increases in ammonia and nitrite. Hopefully not. But when you disturb the gravel bed, you might stir up all kinds of gunk that otherwise would have slowly decayed. The result may be similar to a nutrient surge, as if you dumped in way too much food or added to many fish too fast. Look for it, if it happens, then do some water changes. I would think it would only last a few days to a week at max, if it occurs at all. If you use new gravel, this probably won't happen, unless your filters biologic media isn't established enough or of sufficient quantity. Dont skip reusing the old gravel because of this, if you want your old gravel then move it and keep an eye on things.

[Fishyfanatic]

I agree with Mrcrazy, if you can upgrade to the 29 gal, do so. They are generally not much more expensive and it will open your options up. I'm glad that you decided to upgrade on the tank. 10 gal isn't enough room for just 1 molly. They need their swimming space. I recommend a minimum of 29 gal because they are so active. To seed your filter, run the new filter on the 10 gal tank for a few weeks. Then transfer the gravel and decor to the new tank. No need to save the water because it doesn't hold any bacteria. As long as the filter is seeded, you won't have any problems. Then after you move the tank, run the filter from the 10 gal on the 29 for a few weeks. This should eliminate any kind of mini-cycle.

If you have the space, you could also get a 5 gal tank for the Betta and set it up on your desk or in the kitchen. That's what I did. My male betta loves to look out the kitchen window. They are alot smaller than a 10 gal if you're concerned about the space issue.

[rich311k]

I have just one thought. I know you said you are putting the new tank were the old tank was. If it is on a piece of furniture and not a stand, bear in mind the 29 gallon tank ways almost 300 lbs as compared to the 100 lbs you have now.

[Sprank1]

I think I will stick with going to a 20 gallon long tank (I know the 29 is the same footprint, but height is an issue for the location). I am sure the piece of furniture will hold it. It is a very solid built-in cabinet which is made of 1 inch solid pine with a lot of support.

I may take the Betta and place him in his own smaller tank - probably a 3 or 5 gallon tank which I can put in my office upstairs. If I do that I will probalby make the 20 into a brackish tank. If I do that, can I still have live plants in it? That was one of the things I wanted to do when I upgraded to the larger tank.

Again - thanks for all the feedback, info and suggestions.