Tank Cycled After 28Days Fishin Cycle?

[Hydra]

I've a 120 litre tank with a fluval u3 filter, I filled it up with water 29 days ago & the following day added 5 zebra danios, I didn't really understand the fishless cycle at the time so went the fish-in route.
When I understood the cycle I immediately start doing nightly 25litre water changes to remove the ammonia & ordered an API masterkit.

I'm now 28 days in, have 5 happy danios & it looks like I have 0 ammonia, 0 nitrates & about 20-30 nitrates. I know that means my tank should be cycled but I'm slightly colourblind & can't trust the tests 100% so I'm wondering, could my tank be cycled already, ie after 4 weeks???
I've a couple of live plants I added over the weeks so I'm sure that helped?!?
 
I switched from nightly to every 2nd night water changes on sunday, ie no water change sunday or yesterday, wondering should I bother doing tonights or leave it alone & just do weekly now?

Any advice appreciated...
 

 

[Fishmanic]

you should test it daily and can do a partial water change just weekly as long as ammonia reads  0 and nitrites read 0

 

[Hydra]

Thanks for your reply, does that mean I can buy a couple of fish tomorrow?
I'd like to get 6 rummynose tetras & 2 cory bottom feeders tomorrow, is that too much to add to the 5 zebra danios in a newly cycled tank at once?

 

[daizeUK]

A 'couple of fish' might be alright but 6 rummys & 2 cories ain't a couple of fish, it's 160% of your current bioload.  Take it slow.

 

[Hydra]

Thanks, I won't go mad so.
What about the 2 corys? would that be OK? or 6 little rummys? my danios would be double the size of the rummys I'd be buying.
I think I'd prefer the cory catfish though first, unsure now, I didn't think my tank would be cycled this quick.

 

[CrimsonBoli]

I would get the Cory's first, although Cory's should be in a group of 3+ i believe?

 

[the_lock_man]

No. Cories, as with all shoaling species, should be in a group of 6+.
 
Obviously, this is impractical for the OP in this situation, so getting 2 is fine for the moment, but I would recommend getting another 2 cories in a couple of weeks (so long as ammonia and nitrite have stabilised again) and the another 2 a couple of weeks after that (with the same caveat).
 
After that, go for the rummynoses, you could probably go for 4 initially, and then another 2

 

[CrimsonBoli]

No. Cories, as with all shoaling species, should be in a group of 6+.
 
Obviously, this is impractical for the OP in this situation, so getting 2 is fine for the moment, but I would recommend getting another 2 cories in a couple of weeks (so long as ammonia and nitrite have stabilised again) and the another 2 a couple of weeks after that (with the same caveat).
 
After that, go for the rummynoses, you could probably go for 4 initially, and then another 2

Then I also need a couple more Cory's...

 

[Hydra]

Cheers everyone, I got 4 rummy tetra, they are about half the size of the danios so hopefully should be ok. I did want 2 sterbai cory but they had none in the shops I went to.