JettsPapa

Shrimp is still the correct answer, especially in a tank that small.

Shrimp carry their eggs until they hatch, so in order for the fish to eat the eggs they would need to eat the shrimp itself. I don't have any experience with rice fish, but while most fish will eat shrimp given the opportunity, with adequate hiding places the shrimp will probably reproduce enough to sustain a colony. I keep mine with guppies, and the shrimp do just fine. By the way, unless the rice fish need it you can remove the heater. I don't have a heater in any of my shrimp tanks, or in the shrimp and guppy tanks. The temperature in my house ranges from 60° F at night in winter to 72° F in summer. I leave shrimp outside in tubs year-round. They're in the shade, but the air temperature ranges from well over 100° in summer to sometimes low 20°'s in winter (I've had them do just fine with the top of the tub iced over for a day or two).

I'm sure it has a height limit, but it's pretty far up there. I have corkscrew val, which as I understand it doesn't get as tall as the regular val, and it reaches the top of my 65 gallon tank and then lays over, so it's probably 36" or more.

Several of the ones I mentioned above, especially the usteriana, get too large for your situation, but the wendtii should be okay. It's probably the most common one, so you shouldn't have any problems finding it, and there are several color varieties. I have a reddish crypt that never seems to get over about 2" tall, so would be perfect for you. I wish I knew what species it is, but I don't have a clue.

I haven't grown dwarf chain sword, so I can't help with that. I have grown Crytocoryne wendtii, which is probably the most common species, along with spiralis, usteriana, undulata, pontederiifolia, and probably others. Spiralis is the only one that hasn't spread to make more plants. It looks healthy, but it just sits there.

I wouldn't worry about it. When the time comes I'd be very surprised if he doesn't take care of both of them. Also, you may already know this, but the koi females, like yours, are notorious fry hunters. I had two or three of them with a male in a relatively small heavily planted tank for quite a while. The owner of the store where I bought them told me they were bad about eating fry, but I liked them so much I wanted to try anyway. The whole time I had them I saw exactly one fry, and I only saw it once.

I would encourage you to go slow with the frozen blood worms. They might not eat them right away (I didn't mention it yesterday, but it took mine a while to figure out that they were good to eat), and they don't need much. Two or three per feeding is probably enough.

I'm afraid keeping vallisneria in a shallow tank will be a constant struggle. I'd suggest trying one of the many crypt varieties. While there may be an initial melting period (like with most aquatic plants), most of the crypt species are easy to grow, and don't need special lights or CO2. In fact they often do well in relatively dim light.

When you decide you might want to post about it here. There are a number of members here who raise and ship fish and shrimp. I can't promise you won't get scammed through this or a similar forum, but I'd be surprised if it happened. I've had dozens of transactions, both buying and selling, and haven't had a really bad experience.

Mine will eagerly eat frozen blood worms, but I don't think that would be good for a steady diet. It seems to do just fine for weeks eating just snails when I don't get around to feeding bloodworms.

No, it's not. Some fish keepers who have fish that are particularly sensitive to water quality routinely change more than that. As long as there isn't a big temperature difference, and you're treating the new water to neutralize chlorine (or whatever your water system is using), it's fine. The only other time a large water change can be problematic is if a tank hasn't had a water change in a very long time. The fish will have adjusted to the gradual changes in the water parameters and may not handle the large change.

Changing six gallons in a 65 gallon tank won't have much effect. If you want to get nitrates down I'd recommend considerably more. The math is pretty easy. If you want to reduce nitrates by half you need to change half of the water. A 25% water change will reduce the nitrates by 25%.

First, I wouldn't feed Bacter AE. While I've seen some shrimp keepers say it works well for them, I've also seen an alarming of reports of it killing every shrimp in the tank. I have never used it, and my shrimp grow and multiply just fine. Even people who do use it say to feed much less than the directions recommend. Since they're in a tank with fish you don't really need to target feed them, but of course you can if you want to.

I wouldn't plant it in a 29 gallon tank. Cryptocoryne spiralis is another good option if you want something that looks similar to jungle val, but doesn't get nearly as tall. The only drawback is that it doesn't spread like jungle val (or at least it doesn't for me, and other crypts do).

You can let just about any aquatic plant float, at least for a while. Some people keep water wisteria floating, and it will do fine that way, but I plant mine. I just don't like the way it looks floating.

That shouldn't be happening. I suspect you have very low quality flakes, or you're feeding too much.

Shrimp

First, you mentioned a colony of endler's. Since you said the tank is for an inexperienced fish keeper I wouldn't recommend that. They likely won't want to deal with the fry. However, a group of all males would be a good option. Eight to ten of any of the nano shoaling fish (chili rasboras, ember tetras, celestial pearl danios, etc) should also work.

160 ppm is pretty high, though I think that 20 ppm safe level is overly cautious. You said you did two water changes. How large were they, and how much did they reduce the nitrate levels?

Guppies do okay for me when the air temperature gets down into the mid 50's, in 20 gallon unheated tubs, but I don't know what the water temperature goes to. I don't know if that helps or not. I don't think anyone can give you a definitive answer on whether or not you should add another heater without knowing how low the air temperature will get, or for how long. Is there any chance you could move them to a larger container? The water will change temperature more slowly with larger volume.

I have a dwarf Mexican crayfish in the 5-gallon tank on my desk with shrimp and a few guppies.

It's not a bottom dweller, but I was at 360 Aquatic in Houston a while ago and they had some leaffish (Monocirrhus polyacanthus). That's an oddball I'd like to get one day.

I'm just fine with anything up to at least 40 ppm. In fact, I add fertilizer when it's much under that level.

I'm not aware of any products to reduce nitrates, other than live plants. Water changes will help, of course, assuming your source water doesn't have high nitrates. You said your nitrates are "out of whack," but didn't give a number. What is the level?

Pearl gouramis would be a good choice. I don't think five would be too many (with mostly females, of course).