Buying Used Tank - Advice

[eduller]

Hello!
 
I've been looking at used tanks, and I found a nice big one for a good price. I was wondering if anyone could tell me if there's anything I should be on the lookout for when I go take a look at it.
 
90 gallon long tank, $150, negotiable
The ad states: good shape, no leaks, 2 cascade 300 filters, 2 heaters, glass lid, top light, metal stand. It comes with gravel, plants (artificial I believe from the picture), misc decorations. I can also take the fish if I want - 2 long finned black skirt tetras, 1 large pleco, 4 red-blue tetras. Seller says the fish are in good health and the tank has been established for 5 years.
 
 
My questions: being that these fish are much larger than my current small group of 3 glofish, will they eat the glofish? If I do not take the fish (which I'm not sure I will because I really am in love with my little glofish), since this has been an established tank for some time, do I need to cycle it before I move my current 3 glofish and 2 snails over? I will definitely take the gravel and plants, since they should contain all the beneficial bacteria, right? Should I fill it and run for 24 hours and test the water? Are there any warning signs I should look for before I take the tank? Obviously I'd look at overall cleanliness, how healthy/active the current fish appear, inspect all the equipment for any signs of breakage.
 
 
 

 

[Stimo]

make sure you have a good look at the glass in good light to check for scratches. I purchased a 2nd hand one and looked at it in a dark garage and didnt notice a nasty scratch to the front.
There will be a tiny bit of beneficial bacteria in the gravel but best part will definitely be in the filter media which would have to stay wet especially  if traveling for some time.

 

[eduller]

Oooh good point. I'll bring a bucket for the filter media. Thanks for the tip!

 

[Gruntle]

As long as it still has water in the tank and the filters are running, and the tank isn't scratched, you should be okay. I bought a second hand tank but the previous owners had emptied it so the bacteria in the filter weren't very awake and it took a while to cycle.
 
An empty tank can dry out and you can have leakage issues (and so can filters) but if they're still in use there shouldn't be an issue. I was lucky there.
 
I'll leave the fish compatability issues to others here.

 

[Ryan10]

If you buy it...take a couple of days to fill it up to check for leaks.  It's less messy that way. 

 

[eduller]

The 90 gallon tank sold out from under me. Eek! Okay last question about tank sizes and I'll move along. I know to get the largest tank I can afford. However, is there any disadvantage to a corner tank? It's 27.5 inches x 27.5 inches x something (darn I remember nothing from trigonometry - sine, cosine, tangent, what?? hypotenuse? 38 inches?) It's a 54 gallon corner bowfront for sale, comes with all the important bits. It's $200 and about 40 minutes from my house. I've also found a 29 gallon with tons of accessories including supplies for live plants. It's $100 and about 5 minutes from my house. Dilemma.