What does it mean if your beta fish is turning green and what can I do to cure it?

[BJLP]

My fish was naturally blue and is turning green all mostly at the head and is still blue at the tale.weve had it since october 21 so it is about 4 month old.

[fighterfish]

what kind of green?how old is it?Male or female?A juvanile betta can change/show diferent colours as it is a long slow growing process(so it might just be coming into its colours)Each scale has a cloured(few)or non coloured cell pigments,thus'green to our eyes may have underlying pigmentation that has receeded or mutated to for green/shades of(check genetics)If any other tpye of green,then you have problems my friend.
Try changing water,removing plants&adding a pinch of salt,if nothing else it will help strenghthen scales&coating(mucus layer)
A bit hard,need extra info..
Good Luck
PS:why not take him to your aquarium,they may give you a specific(if its itch,bacteria ect)&you can get treatment medication for him...First up..tank change
colour changing&'flashing'is not uncommon.

[Chaos!]

Turning green? As in all over? Bettas do sometimes change color, and there could be several reasons. The most likely is stress.

What color was he originally? Does he have any other symptoms, like lethargy or bloating?

[Finatic]

Some betta will naturally change colors. Betta can also change colors if their environment is not appropriate.

Betta need to be in water heated to between 75F and 82F. This means you should have a heater and a tank of at least 5 gallons to ensure consistent temp control. It is also important that you NEVER use distilled, bottled or reverse osmosis water for betta..... ever! Betta absolutely need the trace minerals found in tap water. Be absolutely certain that you use a tap water conditioner to neutralize both chlorine and chloramine and that you match the temp of the tap water as closely to that of your tank before adding it into your tank.

If you do not maintain proper heating and water chemistry for your betta, the fish will become lethargic, lose appetite and lose coloring.

Note: Do NOT use table salt in a betta's tank. I would not even recommend using aquarium salt for these surface air breathing anabantids. It is NEVER a good idea to "medicate" a tank just a good measure. Chemicals, medications and salt should NOT be used unless absolutely medically necessary!!

[Ann N. Cephalic]

It's called ich (pronounced ick) and you can get some drops at the petstore to add to the water to clear it up.