My new female leopard gecko hatchling isn't eating. Is it bullying?

Two female geckos cam live together peacefully as long as the enclosure is of sufficient size. Two males should never be housed together. Gender cannot be determined by the images posted. Males can be differentiated from females by the presence of a V shaped line of pre anal pores just in front of the vent and hemipenal bulges behind it. Your gecko appears to be in the middle of a shed. This is a stressful time for geckos. Provide one or two moist hides in the cage and daily soaks to aid in shedding. Feed appropriately sized prey, no bigger than the space between the eyes, that have been gut loaded for 24 hours prior to offering to maximize nutritional value. Calcium w/D3 and Vitamin supplementation is essential to good health. Consider an exam with your veterinarian or an experienced herp vet to diagnose illness or injury. Submit a stool sample to diagnose intestinal parasites.

I commend you for rescuing those Leos! Female leopard geckos may live together peacefully as long as they have a large enough enclosure. Males should not be housed together as they will fight. If you have a male and female, they should be separated until the female is at least 55 grams, which is the minimum weight recommended for breeding. I would guess they may be about 3-5 months old. Hatchlings typically weigh 2-5 grams for reference. There is no "standard" since leos will grow at different rates depending on dietary and environmental factors. You can determine sex by looking underneath. Males have noticeably distinct femoral pores and pre-anal pores. The base of their tail will have two hemipenal bumps as well. You can review leopard gecko care here: http://www.anapsid.org/leopardgek.html

Unfortunately, it is common for intact males of the same species to fight, so you may experience that as they get older. They can be very territorial, and it doesn't matter if they are siblings or not. As you mentioned, male and female geckos can (and often will) mate, no matter if they are siblings or not. If you have two females, this would be the most ideal housing situation for multiple animals. Females will often tolerate one another in the same area, however there are exceptions to the rule, and they can fight as well.

The bump could be local infection or irritation. Monitor it for change or growth. Symptoms to look for are redness, increased swelling, bruising or sensitivity on that side. Make sure you don't have two males as this could lead to stress or bullying which can affect appetite. If you do have two males, provide a larger enclosure with multiple hides for them to use. Feed them separately if you can and use a kitchen scale to monitor the weight of the skinnier gecko. See your veterinarian or a vet experienced in treating reptiles if there is no weight gain or weight loss. Submit a stool sample to diagnose intestinal parasites.

The tank may be too cold. If so, Rita will stay on the mat. Low temps can affect appetite and activity in reptiles. Maintain a basking spot temperature in the 90s F. This will produce a gradient of the mid 70s to 80s in the rest of the cage. You can soak her in a warm 50/50 solution of water and unflavored PediaLyte. This will warm her up and treat or prevent mild dehydration. Feed appropriately sized prey. Crickets or dubia roaches are recommended over mealworms for juvenile geckos. They should be no bigger than the space between her eyes. Gut load them for 24 hours prior to offering to maximize nutritional value.

Offer appropriately sized prey, no bigger than the space between the eyes. Confirm proper temperature as well. Low temps can affect appetite and digestion in reptiles. Be sure to dust prey at every feeding with a multivitamin and calcium supplements. Gutloading prey for 24 hours will also maximize nutritional value. Do not be concerned if she refuses food for one day.

Her growth was likely stunted by poor nutrition and a poor environment. With proper care and feeding, she may "catch up" but be prepared for the possibility that she may not. Do not worry if she doesn't use the hide. She may be comfortable enough in her surroundings to be out in plain sight. An adult female leo will be around 8-9 inches and weigh 50-80 grams. When you can, have her examined by your veterinarian and submit a stool sample to diagnose intestinal parasites. As long as she is eating and behaving normally now, there is no cause for concern.