waterdrop
Enthusiastic "Re-Beginner"
Hi Karen,
You're asking some very interesting questions there and I can't answer them all but thought I'd thow in my 2 cents: Like you, I remember very hardy and vibrant neons/cards from the 1960's and was somewhat shocked to find the lack of confidence aquarists now have in the stock. I've read that neons/cards were perhaps *the* fish that popularized the beginning of the tank keeping practice and helped enlarge it into a mass hobby (in the 1920's, at least in the USA, not sure if the UK hobby preceeded this significantly although I'm prepared to believe percentage wise it may have always been and may continue to be a bigger hobby in the UK.)
In the 1960s/70s my hands-on experience was that cardinal tetras were significantly more hardy than neon tetras. Of course, my perspective was that of a boy buying both types for his fish tanks and observing things, I never bred them or got to talk to importers or experts about them. So I don't know how far my experience back then would have generalized, but the cardinals I had were tougher and the neons were sickly little fish that often died, although once you got some good ones going they could end up getting strong and nice. I always liked both and enjoyed the slight difference in their appearance, the neons having the nice added spash of silver, but the cardinals having the much stronger streak of red/orange.
When I joined TFF, I was shocked to be told by someone that he considered cardinals to be less hardy than neons! I later realized that opinions on this are mixed and that in general its true that both neons and cardinals have suffered genetically somewhat over the years and are less hardy than in years past but its not clear that there a big difference in this aspect between the two. I also now feel that its not obvious at all how much this "lack of hardiness" is truly due to genetics or is being assumed after fish are lost due to tank maturity problems. Both variations of these tetras seem to have some sort of problem with tanks that are less than about 6 months mature. It does not seem to be a cycling issue. There seems to be some other factor we don't yet understand and I feel we are at the stage where the observations are real but the causes are not known. I love how much better a well-cycled tank is for fish and I'd really be happy just putting the explanation to this but I think its more, and I have no trouble believing that there are dozens of factors we don't have the time or money or energy or knowledge to measure that could be the explanation. We measure only a tiny fraction of the things going on in a tank environment.
Many aquarists I know will also admit that there's a time window out there, somewhere around 6 months after tank establishment, where a tank will just seem to "synchronize" or "settle." My observation is that often the water seems more clear, the substrate and plants somehow have changed from a "new" feel, to a more "established" feel. Sometimes the nitrate(NO3) level will drop a bit from what its been reading for previous weeks, even if it was reasonably low during those weeks. I know this sounds wishy-washy but I'm just trying to describe something in words that I've felt seems very real on any number of tanks I've established, including my most recent one I've done here in the last year. Sometimes I wonder if there's a bit of DOC (dissolved organic carbons) that gets finally established and kicks in to make the water chemistry funtion somewhat differently, I don't know, but I know the feeling seems real.
Anyway, back to the cards/neons. My personal feeling, even if others argue its flakey, is that cards/neons are waiting for this moment in the life of a new tank. If that's when they come in then even the smallest, frailest among them will perk up and thrive in their new environment. If they come in before that, say right after a fishless cycle, then there chances change and there may be a struggle for them, with some of the smallest possibly not making it.
Cards/Neons very definately fall into the category of tetras that change behaviour relative to shoal size. They are used to being among millions in the wild and when they get to very low numbers they get stressed (I always imagine they think they are separated from the "mother school" and expect to die!) Anyway 6 or 7 min seems near the "bottom" and each individual fish you add above that noticably improves the situation among them, so 10 should be much better than, say, 6, I'd think. They also relax more and more with better plant coverage nearby. They don't have to be in the plants, they just like to know they're near by. All that should improve the nippiness, but there's a small element of that that may never go away as it just seems to be a personality thing that sometimes some of the larger neon/cards can just be a tiny bit "bulldoggy"... anyway they can hold their own sometimes, exchanging a pretty even number of nips with rasboras and zebras for instance. Its never on the level of problem fish like bleeding hearts or tiger barbs or something like that of course, but its interesting to observe.
~~waterdrop~~
ps. didn't get a chance to say welome in your post in the welcome forum but wanted to say nice to have someone with lots of years to join in with us
