This Is My Tank

Hello everyone, how are you ?
My name is Robert and I have recently purchased a new 42 gallon tank. I cycled for about two weeks and then added some guppies. I waited another month to start more adding fish. I removed the guppies to a 10 gallon and added these fish here: 
2-Molly 
3-Zebra Tetra 
2-Angel Fish pH .
2-Spotted Puffer
2-Yellow Lab Cichlid 
2-Eclipse catfish 

1-Pleco
 
All of these fish were purchased from the same store. The guy who sold me told me I could keep them all together. I only have had mollies and guppies before, so i thought that talking to a local fish store I would get the proper information. After a few days, out of curiosity I started researching who my little fishes were. I know I should have done this before, this is take as my fault, no excuse. I learned that these fish are not compatible. I called back the store and was insulted by the owner who accused me of calling him a liar because I was telling him that these fish do not go together, He made me feel very uncomfortable, and honestly I was scared of going back to the store to return these fish. I am willing to surrender them, if necessary to someone else who can take proper care. My question is, what should be the best action here. How can I remove the least amount of fish and maintain a balanced tank ? They all have been together for 4 months now. I am going to transfer the spotted puffers to another tank, but cannot do as of yet. They are very small. The guy at the store insisted that they can be at fresh water for all their lives (this is when he started accusing me of calling him a liar), Regardless, in a few months they will get their own tank. Can I keep them with the cichlids? What about the eclipse catfish ? Am i raising two little soon to be enormous monsters ?
 
I only have had two casualties, two dwarf gouramis   
Should I add crushed corals to the tank 
I know I am wrong for not doing my homework before, but I want to fix the problem
 
btw, the fishstore where I bought all those fishes has now a beautiful online review from me explaining in details what has happened with me 

 

Hi Robert welcome to the forum I have been in that situation in the past and Im sure many more people will be in the future it is just somewhat unfortunate that its how most people start the hobby
 
So first of all to get a good idea of which fish to keep what is your ph and what tanks do you have available and which will you have available in the future? ie how many tanks do you think you want and can you deal with.
 
2-Angel Fish - What are the dimensions of the tank - really Angels need tanks at least 18 inches tall, though 15 inches with a soft substrate like sand can also work.
2-Molly 
3-Zebra Tetra - Do you mean Zebra Danios?
2-Eclipse catfish - These are also known as Sun Catfish, they are quite active and grow quite large... realistically too big for a 42 gallon tank... They could also become predatory to the Zebra Danios in the future
1-Pleco - Is this a common plec or one of the smaller species like Bristlenose?
 
Basically with the fish you have above they could live well together though eventually they will need a larger tank to accommodate the Sun Cats and the Plec if its a common. Though I think thats a decision you need to look at as if you went for the bigger tank I would look at getting the Danios into a different tank either a smaller one or rehome them, though they do need to be part of a larger tank.
 
The real "problem" fish are the Puffers and the Yellow Labs... they will need tanks of their own
 
I'll start with the Puffers, the biggest problem with them is they have beaks not teeth or grinding plates like other fish so if they do nip or bite they do serious damage... as you mentioned they are not true freshwater fish either. This is a great page of info on them http/www.seriouslyfish.com/species/tetraodon-nigroviridis/ I think its well worth a read, their tank size suggestion is about spot on but I have seen them kept well in a 3 foot 125 liter tank. From what I know of them as well they do best in trios which stops one bullying the other so it might be the case that in the future you add one more to the tank.
 
The Yellow Lab Cichlids are obviously African Cichlids, and need a specific set up, you need around a 65 gallon tank. Something like a Fluval Roma 240 would be a good tank for them. It is a specific set up that you will be able to add other species too but it does require a fair bit of research but the Yellow Labs are a good start for these kind of tanks But obviously that is an other tank...
 
So esentially to keep them all and house them properly, your looking at a 5-6 foot tank for the Sun Cats and Pleco with some of the other fish, then a 4 foot community for the Danios to be housed properly, a 3 foot tank for the puffers and an other 4 foot tank for the Cichlids.
 
If that is too much (and dont worry I totally understand if it is, at the end of the day its not your fault your in this position) maybe you could let us know where you are from and maybe someone on the forum can recommend a store that can help you out. Often if there is a bad shop in an area some of the other shops are used to dealing with the messes they make unfortunately...
 
Hope thats helped
Wills