Guppies

[rigga70]

help! my guppies are going arched shape and dark in colour and then die after about 2 weeks can any one help

 

[WILDER]

How many gallons is the tank.
How many fish and which type.
Water stats in ammonia, nitrite, nitrate, and ph.
Bent spines can be old age, internal parasites, to fish tb.
Check the anus of the fish to see if its enlarged or red and inflamed.
What does it look like when the fish go to the toilet.
Any fish looking skinny or bloated.
Any worms prutruding from the anus.