Help! Is My Columbian Shark Ok?

[CassandraM]

So I have a 72 gallon tank that had 2 Columbian sharks in it. I have only had them for a month and yes I did cycle my tank. I checked all my water readings ie. nitrates, nitrites, PH and amonia and they were all good. I woke up this morning and out of no where one of my columbian sharks was dead. I came home from work and noticed the other one swimming in the tank then swimming upside down on the surface of the water. I am wondering if this ir normal or he it is sick and dying? The sharks is eating normally and it even ate a bit of food upside down. I also do have a bit of an algea bloom in my tank right now ( only the water is green no algea anywhere else) I really need help with finding out if my fish is ok and also how to get over this algea bloom. I did a black out with no food or light and covered it with black bags but 2 days later its green again then I blacked it out for a day and its clear but the water is a bit foggy but not green.

 

[BerryAttack]

have you been doing your water changes? and also is it near a window..
is there enough current in the water that it goes through the whole tank.
are you over feeding?
any other fish in the tank?
what is the temp at?

i had these kind of fish.. one of them would swim upside down.. mom though it was cute -.- then it died.

 

[Essjay]

Is this a brackish water tank or a freshwater tank? Comumbian sharks are brackish water fish. They also grow huge, needing a 7 foot tank.

Can't help with the algae bloom, I'm afraid

 

[WILDER]

Please answer essjay questions.

What the make of the test kit you are using?
What do you feed your fish.
Do the fish look bloated in the tummy region.
Can the fish maintain balance in the water.
Has the tank PH alteredc.
Are the fish laboured breathing, gasping.


A fish showing signs of turning upside down is not normal.
It can be caused by -
Swim bladder
The fish is very bloated in the stomach, causing the fish to lose balance, turn upside down,
Bad water quality.
Poor diet.
To many dried foods.
Internal parasites.
Bacterial infection. Infection of the swim bladder.
Injury of the swim bladder.
.