First of all, if the water quality of the fish tank becomes worse, such as harmful substances such as ammonia or hydrogen sulfide, it may affect the health of the turtle. In addition, dead fish may also cause bacterial or fungal infections, which may cause turtles to get sick.

Secondly, if there is insufficient oxygen in the fish tank, it may affect the lives of turtles and fish. Both turtles and fish need enough oxygen to breathe and survive normally. If the oxygen content in the fish tank drops, it may lead to health problems of turtles and fish.

However, if the fish in the turtle tank are cleaned up in time after death, it will usually not have a long-term impact on the turtle's health. Measures such as cleaning fish tanks, changing water, disinfecting fish tanks and replacing filters are helpful to reduce the impact on turtle health. In addition, regular inspection of water quality and oxygen content and keeping proper feeding density can also reduce the impact on turtle health.

Generally speaking, if the dead fish in the fish tank are properly handled and managed, it will usually not have a long-term impact on the health of turtles. However, in order to ensure the health of turtles, it is necessary to regularly check and maintain the water quality and environment of fish tanks.