Tummy time

1 hour and a half to 2 hours in many sessions..
I used to do sessions of 20 min when she was 4 months.. now she is 5 months and just wanna be on the floor.

she HATES tummy time i can only leave her down for like 2 or 3 minutes before she starts screaming

I have a same issue, I just started using the pilates ball, he is much better now

I tried the crab with my oldest and it scared him so idk aboit that but ill look into the aquarium. Shes really good at holding her head up but shes refuses to put her arms anywhere but her sides

that's pretty normal.. mine hate it too, she would scream her lungs out.. I actually asked the ped as I was afraid she was hurting somewhere.
Eventually she got used to it and now she loves it.
Tummy time is basically exercising.. most babies will not like it, but they will grow to love it once they start gaining strenght and acquiring new movements like rolling both ways.
And yes, the crab worked very well for me, as well as hey bear..