New aquarium, how many Dwarf puffer fish?

[Boffer]

Hi, I have a 350 liters Aquarium, whit 9 kg biohome ultimate media, that I has just finished a fishless cycle whit fish food.
And have put in 6 small Otocinclus affinis, 2 of them already dead, i think it was a mistage to buy them first, i have read that it best the tank is 6 month old, I wrote that after I bought :/
But i have now decided to put Dwarf puffer fish in insted of steam fish and Dwarf Gourami, and Otocinclus affinis

But how many Dwarf puffer should i put in? i was also thinking putting some Amano Shrimp to eat the algea, and some Bbronze corydoras because they're sweet and cute, would that be a bad idea to put them together?

Anumoark : 0
Nitrit : 0
Nitrat : 20
GH : 15
KH :13
PH : 8

[Pufferpunk]

Otos are tricky--you must always check that they have a rounded belly when purchased.
350L, you could have around 20 DPs. Cories have been known to get picked on by them.

[Boffer]

Thanks for the answer, okay i know that thanks, there is one there is about to die, but the 4 others is eating algae, and got one of them to eat a squash, so I think they will survive the 4 of them, how big of a group should I have of the Otos, is 4 enough?
Okay that's a lot of DPs :O

[Pufferpunk]

It's 350 liters, not 35, right?

[Boffer]

Yes it 350 Liters