HELP! My betta's person in charge is turning black?

HELP! My blue male betta's head is turning black! Not only that. he used to other go to the top of the water. but know he's always on the bottom and any in his little house or hidden somewhere! He doesn't move and sometimes if i move the bowl he would swim really sudden and scared.

yes i have a filter. but it's a sponge filter and there's a tube in the middle that have bubble running through it.

in the same spherical big bowl is a guppy and 4 tetras.

awee poor entry must be sick D:
get a new cistern its overcrowded and her prolly has amonia burns hope he gets better


hope this helps Seth
Answers:    You have too frequent fish in the bowl. The black could be due to ammonia burns. Invest in a tank, it would form your fish happy.

~Ammonia can be tested using strips from the pet store. Ammonia builds up when there are too many fish within too small a space. In any amount it is lethal for fish.
You need to get a heater for one entry all those fish if not heated will die off. If it's smaller amount than 3 gallons they will need this heater
http://www.bizrate.com/fishsupplies/oid6...
You can find them everywhere
Secondly if it's purely a big bowl it won't do; the ammonia will spike big time, and he will have a reaction to that too. You need a 2.5 gallon aquarium or greater and another article, the 4 smaller tetras are great for picking on other fish nipping flowing fins.

Get an aquarium water test gear
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