Why is my male red ear slider biting the female? What to do?

Separate out the aggressive one. It could be nipping due to hunger, stress or aggression. Consider hand feeding to avoid accidental bites as well as dividing them into two tanks to provide more space. As they mature, they will require a significantly larger space. This number of turtles ideally will need a tank in the hundreds of gallons range or a small pond. A general guideline is 10 gallons per inch of turtle. Sexing turtles is easier when they are mature. Without knowing the species, it can be difficult, but in general, females are larger than males. Males have a shorter, thicker tail in comparison and usually have longer front claws. A female will have a flat plastron whereas the male will have a slight concavity. Males have a v-notch at the rear of the carapace to accommodate the tail when mating. Lastly, you can check the cloaca, or vent. Females will have a rounder vent closer to the body whilst males will have more of a slit farther down under the tail. All these differences are best seen when comparing two turtles or a proven pair.

Juveniles smaller than about 4 inches are difficult to sex. Once they reach that size or larger, it is quite simple.Female sliders are larger, have shorter front claws and thinner. smaller tails than males. Males can be territorial and could "argue" if the tank is not of sufficient size. Ideally, you want to allow about 10 gallons per inch of turtle. Sliders can get big (12 inches fully grown), so be sure you have the space and budget for a large tank.

A gravid (pregnant) RES is very particular about the site she chooses to lay her clutch of eggs. Substrate, temperature, lighting and humidity all play roles in selection. Follow the link for information regarding mating, egg laying and incubation. http://www.redearslider.com/reproduction.html Gestation is about 8 weeks after mating. If it has been longer, TeTe should be examined by your herp veterinarian. An injection can be given to stimulate laying. If you are not set up for incubation or don't have buyers lined up, you can discard the eggs. RES are not endangered and are actually over populated. You can easily find yourself overwhelmed with hatchlings as a female RES can lay several clutches each season if conditions are right.

It may be due to coloring from the food or tank furniture. It may also be a water quality issue. Look both turtles over for any signs of obvious injury. If they are both female, you may have some aggression/territoriality issues which may require a significantly larger tank or separation.

Turtles don't need to mate. Check his foot for signs of injury or infection. This may include redness, swelling, bruising, bleeding or discharge. If you see anything, have Pepper examined by your veterinarian or a vet experienced in treating reptiles. In the meantime, confirm adequate water depth, quality and temperature. You can review red eared slider care information here: http://www.anapsid.org/reslider.html

I wouldn't recommend keeping a smaller turtle with a larger turtle. Oscar would harass or try to eat the smaller turtle. Red eared sliders can be quite territorial and aggressive towards other sliders. If you have a huge tank, say over 100 gallons, it *may* work. If you are set on having another turtle, look for one that is similar in size. The problem with mixing species is that there may be care and environmental differences that you may not be able to overcome in order to provide adequate care to both species.

Males have longer front claws and a longer, thicker tail. Determining sex can be difficult in turtles measuring less than 4 inches. Consider separating the turtles until the smaller one is larger. Sliders can be quite territorial and a larger turtle may injure a significantly smaller one.