First off, let me welcome you to the hobby. I'm afraid to tell you you've already made some of the most common beginner mistakes, but hopefully we'll be able to fix them. :)

The very fist thing you need to know about is the nitrogen cycle. Fish give off ammonia as they go about their daily lives, eating and pooping. Ammonia is highly toxic and can quickly stress and kill them. That's where bacteria come in. They'll find their way into your tank and eat the ammonia, and they'll give off nitrIte in turn. NitrIte is toxic as well, to a lesser degree. But fear not, because more bacteria will eat the nitrIte and give off nitrAte. NitrAte can get to much higher levels before it becomes toxic. In a properly set up tank, you should have to do no more than 20-30% water changes per week, once the bacterial colonies have established themselves. While the tank is cycling, you should test the pH, ammonia, nitrites, and nitrates daily to ensure your fish's health. After that, test weekly before water changes. It's a good idea to record your results at first while you're getting a feel for what's normal for your tank.

Because you added a lot of fish at once, there's going to be a lot of ammonia in your tank very quickly, meaning that you're going to have to do *a lot* of water changes, and you could lose some or possibly all of your fish. Call the store you bought them from and ask if they'll take them back for store credit. You can buy more fish later, adding them slowly once the cycle is complete.

Another reason you want to return fish is because, even though they may be small now, those fish won't fit in the tank as adults. Sure, they'll fit physically, but they'll produce too much waste for how large the tank is, and nitrates will quickly build up to dangerous levels. It's even possible to kill your bacterial colonies entirely with too many fish. A general rule is one gallon per inch of fish, but that's just a guideline that works out well most of the time. (You certainly wouldn't want to put a 10" goldfish in a 10-gallon tank. 10 neon tetras would do happily in a 10g though.) Reduce the amount of fish you have to maybe 10 inches total. (I'm judging that by the fact that I'd use a 1-2" fish to cycle a 10g tank.) Snails should definitely not be in the tank until it's fully cycled, since they're more sensitive than most fish.

Use the store credit you get for the fish (assuming you can) to buy the additional test kits for pH, nitrite, and nitrate. (The tests you want are the liquid drop kind, not the strips. Drops are much less expensive in the long run, and more accurate. I recommend the Aquarium Pharmecuticals Master Test Kit, which comes with all four basic tests and helpful instructions.) You want to keep ammonia under 1ppm, which can be accomplished by doing water changes. After a while, perhaps a week (the time varies), ammonia will go down to 0ppm because bacteria will be comsuming it, and nitrites will spike. I don't know the proper level for nitrites, but I'm sure someone else does. (You see, I made the same mistake you did at first, and I didn't have a test kit, so I have no idea what numbers I used to keep my fish alive. But I can tell you that trying to cycle a fully stocked tank takes some doing!) Then the nitrites will drop to 0ppm, nitrates will appear, and you'll be down to weekly water changes and gravel vacuuming. (40ppm is when nitrates will become toxic, so always change the water before then. Weekly should be more than enough to make sure it doesn't get that high.) When your test results are 0 for the first two and a reasonable range for nitrates, you're tank is fully cycled.

This doesn't mean you can add the rest of the fish at once, however. Your bacterial colonies will need time to grow to consume the extra toxins from the new fish. 1-2 inches of fish added per week is the "rule," but this isn't always possibly with fish who need to be kept in schools. In that sort of case, start the school as small as possible (usually 7 fish), and add to the school little by little.

One other thing to mention is that not all of your fish are compatable. I don't know the temperaments of a lot of your fish, so I can't say anything about those, but I do know that almost all you mentioned are tropical fish, requiring water of about 75*F. I hope you're using a heater or that you will be once the weather cools off. Goldfish, however, are cold water fish. In warm water, they're very prone to diseases. Depending on your species of goldfish, they can get well over 10" and require a whole 20 gallons of water per fish. Common plecos (your sucker fish, perhaps?) get a foot long and also require large amounts of water per fish. This depends on the species though. Also, depending on your species of puffer, he made need brackish or full saltwater as he grows. (Many will be born in fresh water and swim bit by bit into saltier water as their lives progress.)

I suggest either some guppies or the tiger barb school for the purpose of cycling. Any decent fish store should be willing to take your other fish back given the situation, and if not, call around to other pet shops and explain. Chain stores like Petsmart, etc. will not help you though.

As for the filter, using two is a good idea. If you put them on either side of the tank, they'll do a much better job of picking out fish poo and circulating the water. Set them both on low though, to keep the current from being too strong. An undergravel filter isn't required, just filtration of some sort. What you have now will do fine.

Post back to tell us what the pet store said, and keep us up to date on how your cycle is going. The fish-keeping community is generally a helpful bunch of people, and we want to do all we can to make sure you have a happy, healthy tank. :) Be sure to ask all the stupid little questions you can think of. Chances are that they aren't stupid at all.

Return the puffer. They are an extremely aggressive type fish and will be nipping all your more sedate fish in the tank.

Did you buy all of these fish at the same time and at the same place? Didn't the person advise you on any of your selections?

The barbs are very active fish, and guppies are slow moving fish. The barbs will be nipping at male guppy tails.

I have a tank I keep with guppies - and have found that guppies do better with some salt added to the water.

My honest opinion for what it is worth is you have been given some excellent advise please carry it out quickly or otherwise you will not even have one fish alive in that tank.
I know I could easly type out a full page of all the things wrong about you set up. As new to fish keeping you have made the big mistake of just buy buy with out the knowledge of aquscaping, filtration, water chemistry, and just general fish keeping.
Next do a lot of reading and research and locate an extremly good LFS where you can get some good advice.

Keith

You won't have to worry about the guppies, the'll disappear soon. Puffers can eat fishes bigger than themselves [goldfish]. Tiger barbs are also very nippy. You have to decide what type of fish you want and get compatible tankmates. Also as the tank cycles you'll probably have a crash where only the hardiest fish survive. I know it's tempting to get lot's of fish for a new tank but is usually goes through a cloudy water and die off phase. Have patience, you'll get it right.

Thank you all for your information. Even though I am going to post things that you may not recommend or just don't agree with, I still want your opinions.
I had a black goldfish with big eyes die already, I returned the dead fish back to the store, but did a bad thing....I bought a red belly pacus.
Why is it that if one wants more colorful fish, one has to either buy saltwater fish, or aggressive freshwater fish?
Some may think I'm heartless but I tend to see things a bit differently. I will not introduce any more fish. I will watch to see what happens on a daily basis. If some fish eat the guppies.........oh well. I couldn't believe that the person who gave me this 65 gallon tank had it for 50 guppies to swim around in. I want a tank full of fish of all different sizes and colors. I ordered a uv filter to kill algea or that green stuff (I don't have any green stuff yet), and any bacteria to reduce the likelyhood of diseases. I have decided to keep the fish.
As soon as I put the tiger barbs in, they started nipping at the guppies, one tiger actually ate a baby guppy. When I introduced the sharks the tiger barbs stopped the hyper activity. The puffer stays by himself, no one messes with him. I've seen the goldfish lick on the pacus. I found that the pacus has eaten quite a few snails. A frog came with the tank and all it does is play with all the bubbles.
I introduced all the fish about a day apart. I put a new plant in since all I had was fake ones.
Thanks for the input, anymore comments are welcome.
I guees it's kinda like an experiment.

At the risk of sounding rude, but your first post in this thread was asking what people thought of your set up. Some excellent advice was offered - and one was given with quite some detail. This was advice from experience, not opinions on theories about fishkeeping. You also said that you wanted to watch the guppies grow, but then say oh well, as the guppies are being wiped out. I will decline to offer anymore advice since it appears you just want to experiment.

There is a big difference between asking for advice and just wanting to experiment. Some excellent advice was given, but you choose to ignore the advice. I think you need to make more informed decisions by doing some research before making any more purchases. If you don't do this I don't see you in this hobby for long. When you get serious by all means ask a question but until then NOT!

I want to see small fish grow to be bigger fish. I do want the more aggressive fish to keep the guppy numbers from exploding. Some suggested that I should return the fish because they are incompatible or because I introduced too many at one time. Also that the type of fish I chose may outgrow the tank.
Well, this was an existing tank that was running before I got it, it had fish living in it. I realize that not all fish are going to get along together, but I don't have a list of all the fish that are peaceful, and out of those which ones are the most colorful, I refuse to have a tank full of crappy guppies. If some fish grow too big, they can go outside into my outdoor pond (goldfish etc).
It is an experiment in that I'm trying to keep what the store labeled as "peaceful fish" with ones that were labeled "semi agressive fish". There are things that I've learned thanks to those offering information. The lady at the store told me about ammonia, so I got the test kit. She didn't tell me about PH, Nitrates and Nitrites which I learned here on this forum. Also, I learned about adding salt here on this forum. I learned that an undergravel filter is not required and that having two filtration systems is ok to have. Finally I learned that I'm going to need a heater at least for the winter time.
Is the knowledge I gained worth it? Yes! I appreciate everyones comments regardless of how rude they sound.

Now, please can anyone give me some names of fish that are peaceful or semi aggressive that will grow bigger than guppies, and have beautiful color?

Well my experience is only 35+ years possibly more years than many posters. Also been interested in Aquariums for as long as I can remember and that is about 65+ years
(learned about adding salt here on this forum) Yes salt can be added but not all fish can tolerate salt.
(learned that an undergravel filter is not required ) This different of opinion will go on forever I use both UGF and an Eheim Pro11 canister with great sucess.

(Now, please can anyone give me some names of fish that are peaceful or semi aggressive that will grow bigger than guppies, and have beautiful color?) Most people here can give you several fish who fit that request easy, but why bother with you tank and the very little knowledge and experience you have will be nothing but a disaster, the only person to gain from it will be the person who owns the LFS they must be laughing their heads off all the way to the bank.

Keith

"If some fish grow too big, they can go outside into my outdoor pond (goldfish etc)."

The fish actually won't get that big because keeping them in too small an environment will stunt their growth and shorten their lifespan.

None of us has a list of fish that are peaceful. That list would be impossible to make since fish are all so different. We all learn these things by reading about fish in books and on the internet and discussing them with each other. Most importantly, we learn these things before we buy the fish, to make sure we can take care of them properly.

I know lots of lots of beautiful peaceful fish, but I will not give you their names. Animals aren't something to be experimented with simply for your amusement. To me, what you're doing is no different than giving a group of children a loaded gun and seeing what happens. That may be rude of me to say, but I'm hoping the comparison will shock you to your senses.

I wanted a list of names so that I could research and find out more about each fish without buying them. That way if I found the fish beautiful, I would return the fish I have purchased. I've done some research (all on the internet) and I believe that you all are right, I need to decide on whether I want agressive fish or community fish. You all know what are the most beautiful out of the bunch, and if you don't give me names and help me ..........well it will just take me a much longer time to return the fish I bought.
It's like this ..........if I want community fish what fish am I looking at?
if I want aggressive fish, what fish am I looking at?

As far as not helping you if you reread all the above replies you have received some excellent advice on exactly what to do. Your question and problem sounds very familar to another person on a different forum who also will not listen to the advice given. This other person gives another name and country but there are too many similarities in my opinion.

Also there has been a lot of time and effort put into these answers please reread them and take all the advice given.

If you dont it will be nothing but a waste of time replying to any more of your postings as you appear not to be listening to people who are far more experienced than you.

Finally I suggest go to a good LFS and talk to them about returning all your fish before they all die from lack of propper care.

Keith

As soon as I see another fish pick on others in my tank, they quickly lose their home and go back to the fish store. Even a fish needs a clean safe home. They have feelings, and each fish I find has a different personality.