Split tanks are fine. One heater one filter. 5g or 10g is fine. You may have a bit of flow restriction though with a divided tank. IME homemade dividers from craft mesh can be kinda a PITA but very do-able and cheap. They seem to fit better than store bought. I suggest leaving the mesh just a tad longer so it won't keep falling out as you slide it down the spines. What you can do is remove every other square (or every third or fourth) to allow more flow. You will be hard pressed to find a small impeller type filter that has enough surface area to keep the tank clean. Do with a sponge or corner filter filled with floss media. They are less than $5 each. You will need an air pump though.

You will find the 5g and 10g are about the same price. Check CL.

That dog is too cute BTW.

 

Tiffany,

If you have the space, go for the 10G. As Ilikebutteflies says, there isn't much difference in cost. Bigger really is better (up to a point)

Good luck!

 

This is some advice/info I posted earlier this evening.....

I have three Petco Aqueon 10g deluxe tank kits. These are, by far, the best kits I've come across to get for this purpose. It comes with a 50w heater, florescent lighting (which you can get a flora light if you want) and a very decent power filter, which is so simple to baffle. Dividing the two 10g tanks (the 3rd is an undivided sorority) was as easy as pie. I got the standard Top Fin 10g divider, which doesn't need to be cut, doesn't float up, and fits like a glove. My added secret is simple. The Aqueon tank has a thin black lip around the top of the tank. I carefully notched a deep V on both sides where the tank would be divided, and the holding pins fit right in. Holds the divider tight! No slipping. Ever. This also helps the divider lay flush against the glass, so no worries of anyone slipping through! The hood sits right on the divider, so the bettas really have no way of jumping over. Mine have never. Also, the pins may rust (not sure why they are not stainless steel?), so I insert them into the hollow tube, instead of the intended groove. If anyone wants to see pics, I will be glad to provide.

 

Thank you everyone!

Since typing that this morning I have acquired a second 5 gallon tank and I think I'll probably keep my boys separately in them. Though finding space for two 5 gallons is going to be interesting haha Gaston is actually in one now (its unseasonably cold for Iowa and I couldn't keep his temporary .75 gal/quarantine tank warm enough) and he loves it so much I can't bear to have to split it. There's a rather large silk plant in there right now that he seems to enjoy hiding in that won't fit if I split the tank.

I'm still trying to figure out the best filter for their tanks now though. I have a 3 gallon one (unopened so I can still return it if need be) but I've heard talk of 'baffling' a filter? What exactly does that entail - and would it be more effective than a 3 gallon filter in a 5 gallon tank? And what brand of filter do you prefer? Sorry for all the questions

 

I don't have a brand of filter to suggest but baffling a filter usually means to reduce the current strength so your Betta can have an easier time swimming, since they are weak swimmers with their long fins.

Usually the method is to take a piece of aquarium safe sponge and either shove it in the intake of the filter, or to place it on the output of the filter.

Some people use the water bottle method, and there's probably a variety of methods out there. But the aquarium sponge method is more common I believe.

 

I like TOM internal mini filters. They are adjustable and have a spray bar that you can point toward the tank wall instead of having to baffle. They are quiet and IMO, can't be beat as a filter for a five gallon.

 

I have a Tetra power 10 in my 5g. Works perfectly! It is baffled with a bottle and a piece of sponge at the outtake flow.

 

About the tank I would go for the 10 gal so each betta would have at least 5 gallons filter umm not sure I have 3 different tanks two 5 gallons and a 55 gal I have bettas on each one the current on the 5 gallons is kibd of soft cause the filter is at the top as a fountain so is not that strong i'll post a picture and on the 55 the current is heavier than the 5 gallon but at some spots mt betta has found the spots with low current and he's always around that area I don't know how would it work on a 10 gal but I would get one of those cascade filters and place a plant or something in front of it to avoid strong current

 

So on the 5 gal the light is the filter abd water goea to the top and falls down on the 55 I have 3 different filters one for up to 50 gal one for 20 and one for 30 gal but my betta is always swimming on the middle or on the bottom close to the trees sometimes he hoes to the filters to kind of play with the current

 

Two 5g tanks is better than a split 10g--- shallower, with more floor area. It's also a great application for sponge filters. You can use one airpump for two filters, which keeps the cost down. And Betta like sponge filters for their low current.