[Draug Isilme]

Sorry about your misfortune.... It'll help to answer your question if you give us more details so we can determine the cause:
What size are your two tanks?
How often do you change the water?
What kind of water conditioner do you use?
Do you add any other chemicals other than the water conditioner?
Do you have a heater?
What's the temperature of your tanks?
(if the tanks were large enough) Did you cycle the two tanks before adding your fish?
Does it seem like they have other health problems other than turning colors (clamped fins, white spots, fins deteriorating, less of an appetite, bloating, etc.)?
*~*~*~*~*
Sorry for the 20 questions, but usually answering them can make the difference in telling what could be effecting them- whether it's water quality, parasites, temperature, sickness... it really makes a difference! If you can manage to get your fish back to health, they'll definitely be able to survive the trip- Some sites people bid on bettas and are shipped from places like Tailand and STILL manage to be okay xD

 

[Draug Isilme]

Yep, lack of conditioner can definitely make a difference.. A friend of mine tried changing the water without conditioner before and the poor betta looked almost like it was on deaths door... Once she got conditioner, though, it was almost like it never happened and the betta was swimming around all happy ^.^ Anyway, you should look into prime- it seems kind of pricey at first, BUT... the fact that 1mL can treat 10 gallons, all you need is about 2-3 drops per gallon! It goes a long way and for someone having money troubles, Prime does everything for you AND saves money in the long run!
Is there any specific reason why your crown tail gets stressed out when having full 100% changes? Just curious 'cause there might be a way to work with the little guy rather than against... Probably help to get something bigger (less water changes/responsibility is usually less stress on not just you, but your fish) BUT! I'm assuming that's not quite so doable since you're having problems getting conditioner for your bettas....
Otherwise (don't take this the wrong way, it's supposed to be constructive criticism), if you don't have time to properly care for your fish then you might not be in a position to really give them what they need. Not saying your a bad owner, it just sounds like this is something that would be more suitable for you when you have the means to take care of your pets- It should be a bond that benefits the both of you where you can enjoy your fish the way you should be able to and your fish can be the happiest little critters on the planet ^.^

 

[Draug Isilme]

calistra: Actually, I just want to point out something- I'm assuming it will depend on the water quality of the tap, but bettas are hardy enough to live up to a month or two without dechlorinated water... I know this because as a kid, I didn't know these things and am guilty of having bettas in these sort of crappy water conditions... And with that being said, it's definitely still recommended to get conditioner ASAP because let's face it: no conditioner = straight up torture... and no animal should be treated that way large or small.

 

[Draug Isilme]

Well, personally it doesn't sound like these bettas are as hardy as the betta you previously had so you might want to take conditioner into consideration regardless. In proper conditions you really notice the difference between surviving and thriving. I like to think with life, the length of how a creature has lived doesn't necessarily mean it was experienced to its greatest potential....

 

[Draug Isilme]

wh00t wh00t!! ^.^ That's awesome to hear!