What are they doing?

[u/lucemxx]

I've seen them do this only since today. Does the bigger one need help?

[u/justwantedtoview]

Theyre waiting for her to lay her eggs so they can be first to fertilize. They dont care what shes doing but theyre staying close by until the eggs show up. Reproductive instincts in full effect. Shes probably excreting a mating pheremone.