Ok, my 55 us gal tank at work I realize is too small for its two oscars. I thought I had more time to get ready for a split, but the little oscar is stressing out the big one. So I purchased a used 90 gal (us) tank for home. I'm splitting up the pair.

My questions are these:

1. I've got a brand new Rena xp3 set up at work now (in tandem with the biowheel that's been on the tank for 4 months since I got it). I'm "seeding" (is that the right term?) the xp3 to get the good bacteria in the new filter to bring home to the new big tank. How long does this "seeding" process take?

2. Once I get the filter seeded, I'll move it home and get the new tank cycling. Once that's completed, I wanted to get some tankmates for the oscar. Are a couple of silver dollars and a Banded Leporinus too much for the tank? I've looked over the excellent tankmates section on the site and think, perhaps, the bio-mass would be ok with one Oscar, two silver dollars, and one B. Leprinus. What do people think?

usually it would take around 6wks or more for your filter to be reasonably cycled.you could add one of the filter aids, like "cycle" it will not do any harm and will speed things up a little.I would definitely add it to your new tank if you are using all new water so as not to damage the cycle in your new seeded filter. I cant see the amount of fish you mention being any problem for a 90g

a 75 gallon should be able to handle the stock list you have without much of a problem. personally i would increase the number of sd's to about 4 since they are a schooling fish.

as for seeding your new filter i would recommend at least 3-4 weeks to ensure that there is some beneficial bacteria present before you move it to your new tank. also if you know anyone who keeps fish you might be able to get some mature bio media to help speed things along

currently i have a 75 gallon with two fluval 404 and 1 oscar 1 green severum 4 silver dollars and a geophagus and they get on fine and my water qaulity is fine i think youl be ok

As always, thank everyone for the thoughtful replies.

I'm wondering, given the amount of time it takes to successfully "seed" a filter, whether it is worth doing it. It would take a similar amount of time (about a month) to get a new tank cycling with a new filter and some feeder/starter fish.

Is there an advantage either way? Seeding vs. starter fish?

1. make sure the bacteria in the filter doesn't die before you put the fish in ~ 24hrs.

2. feeder fish are poor nutrition. There are plenty of prepared foods that are great.

the advantage of starting by seeding the filter is that you dont have to do water changes on a tank of feeders and if you go with a fishless method you dont have to mess with ammonia to build a bacteria base

If I wanted to get a tank up and running in super fast time I would set it up,add filter start,"cycle"then put one fish in. with your 70g you could probaley add your oscar but oscars are really not the best choice cos the mess. Its vital here that you must test the water daily or every other day and make water changes if and when needed. feeding very little for the first 2 wks will help keep water conditions under control. if you do things this way you must test and be willing to make the water changes. the fact you are running your xp3 already will help speed things up. what size is the oscar? if its under 6" all the better.