Crap.....now I'm going to have to admit my overcrowded newbie problem.
I don't know the technical specie names off hand.
I added 6 fish at the start (well my existing 2 guppies, 3 swords were transferred, then on day 3 the new 6 fish were added). They were all lake w. cichlids (got the list at home, but quieter ones). Also 2 angel(koi one died a week later).
Then I added some sharks (2 silver, 2 rainbow), 3 clown loaches, dwarf coral gourami.
What was meant to be last was 2 bumblebee, 1 rusty cichlid, 1 white tail, 1 orange (flameback?) plus handful of neon tetras. Yes the tetras disappeared during the night (lesson learnt).
Of course I saw opportunity and added a juvenile Red Oscar and 2 more dwarf gourami. What can I say...I'm a newbie who became addicted and couldn't help it.
I transferred my 2 pakistani loach (tiny) because they were eating guppy fry (a small tank).
Same day I think I added 2 albino, 2 cory, 1 black knife. All were very small. Albino died next day, then cory next day, then black knife, then albino. Might be one cory left alive (never see it though).
White spot became evident on Oscar and slightly on fins of sharks/clown loan (all cichlids seem clear) after the first few of that last batch started to die.
Note I've added all these fishes in batches about every 3rd day. It's been 2 weeks since start. Tank was newly set up with all equipment, plus the chemical to avoid new tank syndrome (secrum ?). I checked the levels every 2 days and only during the last batch of fish, did the levels go up to .4 for nitrate.
All fish are juveniles (bumble bee, dusty, white tail and oscar are largest at about 10cm max, rest are 4-5cm at most). I did this with theory introducing young together they will establish as community better. I did try not to be stupid with real aggressive territory fish.
I am keeping careful eye on the white tail (colours show his mood and agro), oscar and a bumble bee (behaviour shows his agro). The other cichlids will occassionally test the couple of sword/guppies in there but never catch them (even at night), do the same to the plants. The 3 dominate fish seem to respect each other, have their territories and just keep other fish out of their way.
Oscar is only concern as I saw him with the dead angel (had lost half its body already) sitting in his mouth (undigested) for a few days. The oscar I never see attack a fish, but I sure think he cleans up when there is dead ones around. Eventually he swallowed the remainder of the angel.
I treated 2 days ago after a water change and in 2 days there is no sign of clearing up of the white spot on the oscar and couple of other affected fish. It says retreat on day 3 (after another water change). That will be tomorrow.
I removed all swords and guppies from the tank and in the other small tank they are happy, no illness, and having babies. One very pregnant guppy died mysteriously (almost like she burst???)...but otherwise there is a handful of guppies, swords, 3 bn and all getting along.
All the fish I added in the first 2 batches and have been there since very start of cycling (with the chemical) are still alive and not showing ill health. 1 dwarf gourami died after the problem batch.
No more have died but since they are days apart, probably due for one soon.
Oscar I'm getting concerned as this morning he looked dead, was asleep, but wondering if I'll find him sluggish tonight at feeding and then know he's really sick.
I don't know whether to take out any fish as if I put them in the other tank, they'll just likely infect the guppies/swords. Plus the 5ft tank has the best filtration and is already being treated.
I figured once the fish start to grow and it really is too little space for so many, I'll give away my less preferred ones.
I'm blaming myself for too many fish and stressing them.
If the levels are up at all or I see any increased sickness, then tomorrow I'll take a water sample to a LFS.