When should I introduce a second Emperor Scorpion to my tank?

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

Thanks for reaching out. Oscars are fairly aggressive and will try to eat each other, depending on their size. Be prepared to separate if needed and monitor interactions. Keep them well fed and provide plenty of hiding locations. Good luck.

Probably not, for a few reasons. The first is tank size. Unless you have a large tank, upwards of 150+ gallons, 2 Oscars can overwhelm a smaller tank and filter with their bio load (wastes). Ideally, you want at least 55 gallons per Oscar. Another reason against it would be that if you end up with 2 males, it is likely they will be fighting constantly until one is injured or worse. Lastly, the long fins on the fan tail will invite nipping which will cause injury and may lead to infection.

Males are difficult because they can be territorial. This can result in aggression and potential injuries. Mixing different species is never recommended. Introducing a female may be your only option, but you risk breeding and unwanted or accidental clutches of eggs.

Hi thanks for using PetCoach. It sounds like you’re doing a great job introducing Sebastian and Cosmo. I would probably give it a little more time before you cage them together 24/7. Continue introducing them in a neutral territory. Here is a bit more information on introducing GP. If both guinea pigs are mail, it may be a good idea to consider neutering them as males can often be territorial. http://www.guineapigmanual.com/introducing-new-guinea-pigs/

Thanks for reaching out about your arowana. These are tough fish to co-habitat in an aquarium as they tend to eat other fish and can be territorial. Introduced fish must be large enough to not appear as prey and not too timid, or will hide and not compete for food. This readily depend on how large your arowana is at present. Good luck.

Ideally you would quarantine any new Fish in a separate aquarium for a few weeks to make sure they do not show any signs of diseases or infection. Once 2-3 weeks have passed without any signs of a problem then it is usually pretty safe to introduce to the common aquarium. Good luck and I hope they do well!