I am here responding to the several issues in post #29. This agaiin will take some explaining (= lots of words
).
So, for someone who has more experience with illness - does the above symptoms (gaping mouth, odd swimming, being a loner and having another of the same type pass w/o symptoms) indicate a water issue (beyond the traditional Nitrates etc.) or does it seem likely that there could be an illness?
If it's an illness I definitely want to treat it - if it's a water issue, I'm hoping more frequent water changes will help solve it; but if it's medical I'd rather know sooner than later.
The symptoms can be due to almost any issue. Water conditions are often the issue because of the close inter-relationship with the fish's physiology. They may weaken fish allowing other disease issues to gain a foothold. Genetic problems. Internal injury during netting/transport. A disease carried on the new fish (or already in the tank to which the other fish are "immune" but not the new Serpae because they are under severe stress from the move).
Turning to adding medications, chemicals, treatments--almost always this will only make things worse. As I explained previously, every substance added to the water gets inside the fish, and this adds stress (at the very least) but may go much farther. If one can identify the disease, and then determine the most effective and safest treatment, fine. I tend to do water changes first, checking conditions and parameters, and only take action if I have good reason to expect "x" or whatever.
Regarding water parameters (pH, kH & gH), I understand that for some fish the water parameters are less than ideal - this is typical for any community tank. I know that community tanks can get a bad rep for this - I'm OK with that. The community style is mostly for my 3 year old son; I'd much rather do a biotype. (and larger!).
This is a critical issue. I tend to think of three categories of fish...soft water species that need soft water period, hard water species that need hard water period, and those species that may be either but can manage in the middle, and there are a lot of these. A community tank must have either soft water species only, or hard water species only, or species that suit middle-ground. Anything else just will not work, ever; the fish cannot adjust or adapt, this is a myth. But within the "middle ground" there are many options. All of my tanks are community tanks, but they only contain species that require those parameters/conditions. This is the first essential step in healthy fish. With this as background...
What would your recommended stocking rule for aquariums? I am pushing the "1 inch per gallon" rule - which to me seems acceptable because:
1. The tank is over-filtered - which means that there is a lot of beneficial bacteria & good gaseous exchange
2. The tank is planted, which has a positive effect on the aquarium as a whole
Each species being considered for any aquarium must meet the criteria of that tank. Water parameters obviously (including temperature, this drives fish metabolism and just a couple degrees can make a big difference to the health of the fish), and aquascaping materials (some fish need sand, some wood, some rocks, some plants--these can be authentic or artificial replacements, but the "substance" must be present). Water flow...not all fish will last in currents, or vice-versa. Light...I always have floating plants to help with this, plus the water quality improves. Shoaling fish need "x" number, and while we are forced into giving minimums, the fish will always be in better health with more than that--always. Swimming space...active fish like danios must have a longer tank than a comparably-sized fish like cardinal tetras, so more of the latter will work in a tank of "x" size than fewer of the former.
Filtration really is irrelevant. It is primarily needed for water movement, and this must take into account the needs of the fish so it is suited to all of them. Biological filtration is important, but a tank should be able to run without a filter--if not, it is overstocked or improperly stocked. More filters or larger filters does not make up for the wrong fish (size or numbers). There is no such thing as "overfiltration" in a beneficial sense; over filtration may harm the fish if it means too much water movement for example. But the substrate is the primary bacteria bed and this is more important.
Plants do help, obviously...but not enough to handle improperly stocked fish. Floating plants are the best for water quality, plus they provide shade.
I mentioned shoaling species need numbers...a larger group will usually have less impact on the biological system than will too few. Fish in insufficient numbers will be under more stress, impacting the system, whereas a few more might have less stress thus less impact. Stress causes fish to react and this is where the system can be impacted.
EDIT. You decisionto return the Serpae is wise...once these settle, they will probably go after the rams. This is a very aggressive species, and it needs 12+ in their own 30g tank as minimum.