Need water stats please in ammonia, nitrite, nitrate, and ph.
Red gills can be due to bad water quality, gill flukes, bacterial gill rot.
Need to rule out bad water quality first.
Signs of gill flukes are as follows -
Red inflamed gills, pale gills with excess slime, bleeding gills, swollen gills.
Opaque body with excess slime.
Flicking and rubbing.
Laboured breathing, gasping at surface of tank.
Red sores, or red pin prick marks on the fish body.
Swimming in a jerky movement.
Weight loss sometimes.
Spitting food out.
Darting, erratic swimming.
Also gill flukes cause bacterial infections, As the parasite carries a nasty bacteria in its hooks or suckers. Which enters the fish blood stream once it pierces the skin.