I really need to get me a 30 gal tank. Just I'm so eager to get a community going and it took me 2 and half months to cycle my 10 Gal. And now I can add fish it just sucks to realize I should have gone bigger. I bet though by using my existing media it wouldn't take me as long to cycle a new 30 gal. And that's probably exactly what I'll do, but Id still like to try this with 10 gal in the mean time.
Now that you have a cycled tank in the 10 g, you can cycle the next tank much faster by swapping out some filter media and substrate from the 10g to the new tank to help kick start the cycle. It's about getting the populations of nitrifying bacteria growing, and it goes faster when you already have those bacteria growing in another tank that can start it off. It's not an instant cycle by any means, and you need to monitor both the tank you pinched the media/substrate from for a few days, and need to carefully monitor the new set up's ammonia/nitrite/nitrate numbers until it's safe to add fish, and as you increase the bioload on the tank (by increasing the number of fish) because it takes time for those bacterial colonies to grow in size enough to handle the additional bioload. I hope that makes sense!
So even cycled tank is always a balance. Even a cycled tank only processes the amount of waste the current bioload produces. Introduce more fish, or more waste (such as a kid tipping in half a tub of food) and there's a problem, because the current bacterial colonies can't handle that much ammonia and nitrite. We handle issues like that with water changes, so you'd remove the excess waste from the tipped in fish food, or to manage the amount of waste being produced by the new introduced fish while the nitrifying bacterial colonies increase in size to handle the increased bioload of the tank.
So don't despair that you'll have to wait months to cycle a new tank. But don't rush it either, and you need an accurate water test kit, one of the liquid test kits not the dip strip ones since you need accurate numbers - to be sure when it's ready, and to monitor and see when it needs water changes/how large the water changes need to be, etc.
Reguardless of the set up.........Does anyone have any information regarding how hardy these two species of Cory are!? Am I better off with one than the other? Let's assume I'm going to get this started with the 10gal but within a few months transferring everybody to a 30 gal tank. But I still have intentions to start this with my 10......... What fish do I get?
My experience is with pygmy corydoras (and bronze/sterbai) and have found them to be very hardy - but mine also went into a heavily planted, very established and stable tank that had been running for more than a year. Whether you're better off with one or the other is impossible to say really, without knowing the final stocking you have planned for the 30g.
I would urge you to wait on getting cories at all though until you have the large tank, and have properly planned out what you want to do with it. You're considering the dwarf species of cory (pygmaeus, hastatus, habrosus) purely because it's possible for a small group of them to live in a ten gallon, and you'd heard they might work with a betta (which I strongly urge against). But a 30g opens you up to a whole wide world of different cory species that you might even prefer, and which might be safer and happier with whatever mid/top level fish you choose for the 30g.
A 30g means most of the popular cories can live in it, with a group of 6-8 (maybe a few more, depending on total stocking) on a sand substrate. Check out panda cories, bronzes, peppered, trilineatus, sterbai, gold laser, green laser - so many beautiful species, and a 30g gives you huge options. See what your local fish stores have that you love when you see them in person (but don't impulse buy!). If you plan to move the dwarf cories (pygmaeus, hastatus, habrosus) over to the 30g, you're also limiting what upper level fish you get much more, since these tiny cories are much more at risk of bullying and being scared of larger fish than a larger, more robust cory is.
So I'd urge you to wait, leave the betta to live alone - the way they prefer to in the wild and in captivity, and so whatever dwarf species doesn't feel trapped and unsafe living with her - and make a proper plan for your stocking for a 30g. You have so many more options with that, don't trap yourself again into keeping a fish you're not wild about, only because they might work in the 10g, when you can plan something truly special that you'll enjoy for years to come.
