Different opinions on stocking - What Do I Do?

Hello everybody!
Today I am going to share a story with you and I really want some answers!
I went to the local fish store, I just wanted to check for any new fish. the guy that owns the store is my friend (more like acquaintance) and I asked him about whether or not they are bringing Black Skirt Tetras? and my second questions was :
Can Firemouth live with Zebra Danios? ( can they really? because it looks very risky if I let a Firemouth swim in the same tank as Zebra danios or any smaller fish)
that was where he started laughing at me...! he told me : "I think you are mocking me, it is a very stupid question, How can a Firemouth live with Zebra Danios?"
he called me a Little Girl because he thinks I am beginner fishkeeper because I only stick with Swordtails, Zebra Danios, Guppies etc....!
He told me that I am a grown up person and I should have Parrots, Yellow Lab, Oscar etc!
But I told him my 60 gallon aquarium is not appropriate for a blood parrot, nor for the rift lake African cichlids and he laughed at me and he asked me : "Who told you that?"
he told me : "Livebearers/tetras/barbs or any kind of fish but Cichlid shows you are a baby fishkeeper"

Sometimes I think he is right and I can mix American and African Cichlid or keep a Parrot cichlid in a 10 gallon aquarium like that guy. Who cares about a fish is happy or not? as long as the fish just swim around and look happy, who cares about a test kit or PH or untreated tap water?

What do I do? do I have to tell him something? he think he does not need my lecture about the nitrogen cycle, and more importantly, a iridescent shark can not live in a 10 gallon but he does not care and he keeps telling me that I am a baby and when everyone just keep agreeing with him, things get really annoying...!

What can I do?

 

I don't think it's worth arguing with him. He doesn't sound like he cares for the fish or you, frankly. I would go to a different store if you can. Don't give him your business.

 

I would just not do business there, speak with your wallet.

 

I don't think it's worth arguing with him. He doesn't sound like he cares for the fish or you, frankly. I would go to a different store if you can. Don't give him your business.

I can go to a different store (the only reason I visit there so often is because his store is in very close proximity to my house)
I think you are right, I do not have any proof of what I say! if I explain Nitrogen cycle for him and tell him if he does not cycle the aquarium first then his fish will die, he will laugh at me again and ask me : "So why have not my fish died without the nitrogen cycle?"

Besides, a little question, I asked him but he just laughed, I want to ask you, Can I have Firemouth with Zebra Danios? (I have to ask this question because it looks very risky, What if the Firemouth wolf them up?)

 

I would just not do business there, speak with your wallet.

Speaking with the wallet is always the best way.

 

Yes, you can keep zebra danios with a firemouth in an appropriately sized tank. The firemouth will eat them if they can fit in its mouth, but adult danios should be okay.

 

Yes, you can keep zebra danios with a firemouth in an appropriately sized tank. The firemouth will eat them if they can fit in its mouth, but adult danios should be okay.

Thanks for your answer!