Looking for some advice on moving tanks

I need some advice on moving some fish that have out grown the tank they're in. I am moderately experienced with fish, I guess I would say. I understand the basics pretty well, nitrogen cycle, maintaining a tank, basic treatments for things such as ick, etc...

O.k., here's my situation. about 5 years ago, I moved, and I was going to be in a temporary living situation, due to my job, and may have had to completely relocate again, so I moved the tank to my mothers house, so I wouldn't have to move it continuously. They've done well, she feeds them, I change the filter, clean the tank, do maintenance, etc... as needed when I go over there. I have not moved the tank again, basically, because I'm scared. In it are, two clown loaches, 6+ inches long, around 7 years old. 1 yoyo loach, probably around 5 years old, and 1 Angelicus Botia, I've had for almost 7 years. Plus a plecostomus, who has to be over 8" long. All of this, in a 20 extra tall tank. It is very well established obviously, a thick layer of gravel, very low maintenance.

So, I need to get all of this into a bigger tank. I am a reptile keeper. I have extra tanks. I have a very clean, sanatized 55 sitting around doing nothing, that would look great with some large loaches. So, how do I go about this? Obviously I need to set the 55 up and get it cycled, but what is the safest and fastest way to do this? Just set it up, get some inexpensive "dirty" fish to get the cycle going? Would it help to transfer some water &/or some of the gravel out of the established tank before the fish to help jump start the new tank? Or would that be too dangerous to the old tank. I don't plan on keeping fish in the old tank if I can pull this off safely. I am apprehensive because I rather like my two large clowns especially. Thay are the two coolest fish I have ever seen.

Thanks n advance for any advice,

Dave

Do you plan on upgrading the filter as well or just use the old filter?
Do you plan to move the gravel over too?

If you simply move over the old filter and gravel to your new tank (without letting them dry on the way, and do it fast), you get to keep almost 100% of the beneficial bacteria. Because these good bacteria are mostly colonizing on your filter media, the remaining are mostly in the gravel but not nearly as much as in the filter media.

The old tank water holds next to 0 beneficial bacteria because they only colonize surfaces. So there is no value in transferring the old water for nitrogen cycle. However, by transferring old water, you actually avoid the chance to shock the fish in new water. even though you use the same water source, the water PH and hardness in the tank as well as the nitrate concentration can be different in the tank and fresh tap water. So you do get some benefits by using the old water.

I think I am going to get a new filter, the one on there is old, it still works well, but runs about 200 gph if I remember correctly, might be a bit weak for a 55 gal tank though. I would transfer the gravel. My question with that would be, timing? Do I set the new tank up first? and get it to cycle first? Would it be safe to just bag the fish, move the gravel and the rest of the water, add new gravel and water, float the fish, then introduce them? I was thinking of trying to start the tank first, getting it cycled, at least partially, then bagging the fish, transferring gravel and water, and introducing fish. What is the safest way to do this, for the fish. There is no immanent rush.

You have multiple options.
Option #1. Get the new filter, and set it up with the new tank. Do a fishless cycle with pure ammonia. It can take up to 6~8 weeks without bacteria seeding. It can be much faster if you seed it with a piece of old filter media from your old filter, or if you transfer a lot of gravel over but it won't be as effective as the filter media transferring. You can also use Tetra SafeStart as bacteria seeding which was mentioned in this article
http://petskeepersguide.com/fishless-cyc...gen-cycle/
Once the fishless cycle is completed, you can move the fish over safely. You can transfer half the water over from old tank before move the fish over.

Option #2. Get the new filter, and have it run along side of your old filter in your old tank for minimal 3 weeks. It will gain bacteria required for the nitrogen cycle. But it is not guaranteed to have enough bacteria to take on all of your fish's ammonia once it is the only filter for your new tank. If you go this router, you can then use the new filter to set the new tank up before moving fish over.

Personally, I prefer option #1 for guaranteed safety reasons for the fish.

I have a question. Do you plan to set the new tank up in the same house as the old tank?