I have 2 gigantea's that are now touching each other. I figured same species and shouldn't be an issue but thought i would check anyways.
The one has just expanded so much the last day or two that they are touching.
Seriously though. If they are both healthy, they will be fine touching each other. If one or both of them is a new introduction, it could be carrying a bacterial infection that can spread to the other.
OKay we'll i am not so sure they are very happy with this arrangment that they have put themselves in. The purple one doesn't seem to really care but i think what has happened is the flow is now getting blocked to the yellow one.
I think it's better if they don't touch but if they do it's really not a showstopper. I have 4, 2 of which constantly touch and 2 of which occasionally touch. There's no issue. I'll try to dig up a thread that shows the first two touching..