Female Betta - Tail Ailment

Look like she might have fin rot. How big of a tank is it and how often do you do water changes?

As for the tank in the back, do you mean food that doesn't become moldy in the tank? I only feed what my betta eats right away floating on top of the water, so I don't worry about food on the bottom. Its much easier maintenance.

Get a liquid test kit and start upping your water change schedule. It looks like the female has fin rot which can be cleared up when you improve your tank maintenance. Feed your betta 3 or so pellets twice a day and never ever let food rot around like that. Invest in heaters and some proper larger tanks so your fish can actually swim instead of mope around dying.

If your water is cold, they MAY want to eat less... but 3 pellets 2x per day is a good rule. I feed 4 2x a day to my larger ones (in 78F water)

2.5 gallons is considered the minimum for bettas to live happily. I recommend Red Sea Nano HOB filters (silent!) and a Hydor mini heater (If you go the 2.5 gallon route.)

It might seem silly to go through the expense of upgrading them, but you will be SO surprised at the difference once they are REALLY healthy! The maintenance you should be doing on your tanks right now is 10000x more work than a heated, filtered tank (as long as it's cycled)

I have 6 bettas in separate tanks (2.5gx2, 5gx3, 10gx1) and it's no trouble at all to keep them healthy. I also have 5 ladies in a 20g sorority. They are a JOY to have... and SO different from when they were cold!

You will be able to find lots of help here if you have any questions about upgrades. If you choose not to upgrade, on 1 gallon tanks.. you should be doing large water changes EVERY DAY (especially important with fin rot going on). Clean water should brighten her up a bit. Medicine should not be necessary if the water is kept clean.

The tank size ISNT the issue. I use the same tanks, and have no issues and do waterchanges once a week. I have 13 bettas and all are alive and well some are almost 2 years old in the same size tanks and thriving. She posted the waterchange she did on Kenzi's tank right after the post. This picture was taken BEFORE the waterchange. I agree waterchanges will be the best form of medication.

Agreed on all of the above. Water changes are definitely a start. getting a small gravel vac would be a great idea for quick cleaning of those pellets. :] When you dont have the time it takes to do a full water change, it definitely works!

I've had no issues with that tank with my small females as long as I did weekly waterchanges and sucked up the gunk in between(walmart at ten bucks right?) and the UG filters work fairly well!

Ash, I hate to be mean or anything(and thats not how I'm trying to act) but the way you 'talked' to her was degrading. She asked for ideas/help, NOT to be told she's taking horrible care of her finned friends.

I didn't say she was taking horrible care... however, such a large amount of rotting food suggests lack of sufficient cleaning. Lots of people have healthy bettas in setups under 2.5 gallons.... is it the best way? not necessarily. And I'm sorry, I didn't realize that she had UGF going. If there aren't heaters, I would still suggest getting some. But yeah... I'm sorry if my lack of emoticons confused people on my tone. Would more smileys make it sound nicer? Sigh.. on topic, like everyone's said, large, frequent water changes should clear up the fin rot.