This page presents experiments on which I'm currently working or plan to start in the near future.

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NEW!!! Agitation versus aeration for brine shrimp hatching!

As this photo shows, a brine shrimp egg goes through a delicate period where the hatching sack could be prematurely ripped away from the egg before it was ready to hatch. Since my hatching rate using bubbling air to agitate the eggs only runs around fifty percent, I theorized that many eggs were being injured by the violence of the aeration. To test this I purchased a slow motion motor and used it to gently rotate a hatching jar at 2 rpm. While the eggs were kept perfectly and evenly suspended in the water, the hatching rate was almost nil. I assume from this that vigorous agitation is not only not harmful, but necessary.

Changing a betta's diet! I had a female betta who had only eaten live blackworms for months. I wanted to give her a wider range of food so I switched here to Bett Bio-gold pellets. For the first five day she wouldn't even look at them, even if I used a stick to move them around. (This usually tempts bettas into trying a new food.) The problem was that after a diet of blackworms, she looked at the bio-gold pellets as rocks or boulders, she simply didn't recognize them as food. On the sixth day, while I was moving one pellet arrounded, she tasted it several times but never menaged to keep it down. The next day she managed to eat one. The day after that two. Day by she increased the number she could handle. By the end of the second week she'd become one of my most aggressive eaters and I no longer needed to move the pellets around to tempt her.

Once-a-week feeding experiment! Although I love bettas, I have to admit that feeding them twice a day, every day, forever, gets to be a drag. So, I've started an experiment to see if I can simplify things by feeding them a large enough helping of blackworms to keep them fat and happy for a week at a time. So far I'm only subjecting two of my fish to this experiment. After two weeks they seem to be doing fine. Unlike uneaten pelleted of flaked food, the blackworms are alive and don't spoil the water. Most importantly, the fish don't appear to be either over eating or starving. The cost of this technique is that you have to maintain a supply of blackworms, which is cheap and easy, and not being able to have any rocks or plants in the betta jars because the worms will hide in them.

NEW!!! Once-a-week feeding experiment update! The two fish I started with have been doing fine on the once-a-week feeding experiment for five weeks. If anything, the water appears to stay cleaner longer. I suspect this is because there is no uneaten food to go bad and that the worms consume some of the fish waste. This system is doing so well that two weeks ago I added two more fish to the experiment. So far, all of them are doing fine.

I received an email from someone who mentioned that when they accidentally spilled a large quantity of worms into one of their betta's jars, it ate itself to death. I've heard similar anecdotes like this before, which raises the question of why mine aren't doing so. I think the reason is that in the eating-themselves-to-death cases, all of those fish were already used to eating worms and jumped at the banquet when it presented itself. My fish had only been fed Betta Bio Gold pellets prior to putting them on the worms-only diet. The result was that the worms represented a strange new food to them so they were slow in adapting to them. By the time the bettas learned the worms were food, they were used to there being an abundance available so they didn't feel the need to gorge themselves.

Does feeding fry too many baby brine shrimp cause swim bladder problems or make them eat so much they explode? The change from feeding the fry in the growth rate experiment only vinegar eels to only baby brine shrimp gave me the opportunity to test this hypotheses. Although there are only 14 fry left, I am feeding them hundreds of baby brine shrimp three times a day to insure they have all they can eat. After one week of this the fry appear to be healthy. Although their stomachs are always packed and bulging, not one fry has exploded from eating too much... or even died. All 14 are doing fine. I have observed that once they get bloated, the fry ignore the shrimp even if they swim up and bump into their faces. It would seem that at least in this test, betta fry will not gorge themselves to death. It will take several more weeks to determine if this brine-shrimp-only diet causes swim bladder problems.

NEW!!! FEEDING TEST COMPLETE! None of the fry developed any problems after five weeks on the BBS-only diet. Neither did they eat themselves to death even though many more BBS were provided than they could eat. I believe the idea that BBS cause bladder problems results from the fry eating unhatched eggs which mechanically damage the fry's insides. In my experiment I was careful to avoid introducing eggs into the fry tank. This experiment is considered complete.

NEW!!! Brine-shrimp-only feeding test update! A brown algae outbreak killed all but three of the fry but I've continued with the experiement. After four weeks, all three fry are developing healthy swim bladders and aren't having any problems swimming. To be continued....

Fry growth rate experiment: What effect does the type of food fry are fed have upon their growth rate? That's a question I'm starting to address with my fourth spawn. The fy will only be fed vinegar eels until they are large enough to switch over to Grindal worms. I measure several of the fry every week to determine how fast they grow on this diet. The next spawn, by the same parents, will be raised on baby brine shrimp and a comparison will be made between how fast the fry grow. I've done some research on several websites and discovered that microworms are considered less nutritious than brine shrimp so the worms won't be tried. Here are the results so far:

Fry fed only vinegar eels (Fourth spawn):

hatched week-1 week-2 week-3 week-4 week-5 week-6 week-7 week-8 week-9

0.10 ... missed .. 0.16 .. 0.175 ... 0.18 ... 0.18 ... 0.25 ... 0.38

(At 5 weeks the fry had stopped growing and were dying at an alarming rate. I switched to feeding them only baby brine shrimp to see if this would fix the problem. It did. Growth on bbs is indicated with green entries.) NEW! As can be seen in the green entries above, the growth rate on bbs is explosive. But, due to unforeseen circumstances I had to switch to Grindal worms so the test is over. The results were: (1) vinegar eels alone are nutritionally deficient and cause stunted growth, deformities, and death; (2) in spite of repeatedly putting thousands of baby brine shrimp into a tank with only 16 fry for a period of two weeks, not one of the fry over ate to the point where they died; (3) the fry grew much faster and healthier on bbs than vinegar eels; (4) none of the fry developed swim bladder problems from eating baby brine shrimp. However, the fry were several weeks old by then. It may be that bladder damage due to too many bbs occurs in younger fry.

This has been an interesting and educational experiment. I hope you enjoyed it as much as I did. For the future, I plan to raise my fry for the first few days on bbs and vinegar eels, then switch to bbs until the fry are old enough to take Grindal worms.


Fry fed vinegar eels and baby brine shrimp (Second spawn):

as hatched .. week 1 .. week 2 .. week 3 .. week 4 .. week 5

0.10 inches .. missed .. missed ..... 0.25 ..... 0.30 ...... 0.45



I stop at week number five because in a healthy spawn the fry should be large enough to start eating Grindal worms, an acknowledged superior food. What this experiemnt shows so far is that fry fed only vinegar eels appear to grow 33 percent slower than those fed vinegar eels and baby brine shrimp. This implies brine shrimp are more nutritous than eels. The third test will determine if brine shrimp by themselves are better than a mixture of brine shrimp and eels.


Using Betta Bio-Gold food pellets to condition a female for spawning: Does a female absolutely need live food to condition them for a spawn? I plan to test this during my third spawn. Blue will only be fed Betta Bio-Gold pellets during the two weeks she's conditioned for the spawn. I will increase the amount she's fed to three feedings a day for a total of 15 pellets. That's fifty-percent more than the recommended diet. It'll be interesting to see how she does.

NEW!!! This question tested! While the third spawn failed because the female was too large for the male, the forth spawn went perfectly with over 100 fry produced. Both the male and female received only Betta Bio-Gold pellets prior to spawning. Many more eggs than fry resulted from the spawn but due to the male's inexperience, many of them didn't get fertilized. I believe this test verifies that bettas don't need live food to produce good spawns if they are fed Betta Bio-Gold pellets.


How to grow a giant betta: I asked a dozen breeders how big bettas get and what factors encourage them to grow large. Sticking strictly with betta splendens, the consensus for the maximum size was four inches. While the availability of plenty of live food and being housed in large tanks were mentioned many times as important for growing large bettas, the most important issue appears to be water quality. Several breeders mentioned that they had grown very large bettas in small containers by constantly changing the water.

I decided to attempt to quantify the effect of water change rates on betta size.

As soon as the fry from my current spawn are large enough to require jarring, they will be sorted into four groups so that each group has the same initial size profile. Each fish will be placed in a 3/4-gallon jar and provided the same diet. One group will get daily water changes, the second every other day, the third every four days, and the fourth every eight days. I'm hopeful that this range of change rates will enable me to formulate an equation that yields final fish size as a function of how often the water is changed.

The results of this experiment will, of course, only be applicable to the fish resulting from my current spawn. Someone applying the results to different fish will almost certainly end up with fish of a different maximum size. But, I hope that regardless of final size, if the results of this experiment are applied to raising that fish, it will achieve its maximum size potential.

I hope to have the results of this experiment posted by August.

Interesting note: While most breeders responding to my questions stated that it was dirty water that limited growth in small or infrequently changed jars, one breeder mentioned that the fish gives off a hormone that limits its growth. More frequent water changes or larger tanks dilute this hormone so that the fish never gets the signal to stop growing. Once I know the optimum water change rate for maximum size, I hope to figure out how I can test this hypothesis.


NEW UPDATE!!! An experiment to determine if betta growth be restarted once it stops: I house my bettas in 3/4-gallon jars and change the water once per week. Ten of them are adults and have shown no growth in the last three months. I'm going to use Royal, my blue pastel, to see if he can be induced to start growing again. On March 8, 2002, I used a vernier caliper to measure his length at 2.43 +/- .02 inches. (The uncertainty is the result of an understandable resistance of the fish's to holding still while I stretched him out on a towel to be measured.) I'll repeat this measurement on 1 April to verify that he is not growing. I'll then begin daily water changes for a month. At that time he'll be measured again to see if any growth has occurred. During this period, his diet will remain the same as it has been. If there is no growth, then I will suspend the daily changes and try instead to induce growth by adding a daily portion of black worms for one month. If that doesn't work, then I will incorporate both daily water changes and daily feedings of black worms. The hope is to determine if water change rate or diet is more important to encouraging an adult fish to start growing again.

NEW!!! On 1 April (no fooling) I measured Royal again. He was 2.53 inches long. That's an increase of 0.10 inches in 24 days. I had hoped his growth would be zero to make any change in size more obvious. However, I will start giving him daily, 100 percent water changes today and maintain the schedule for the next 24 days. If at that time he's gown by significantly more than 0.10 inches, I will interpret that as verifying that frequent water changes do indeed encourage growth, even in mature fish. Please check back on April 25 for the results. Thank you.

I hope to have the results of this test posted by July.

NEW!!! I measured Royal again on 1 May and discovered he'd only grown to 2.64 inches. The 0.11 inch increase is close enough to the increase during the previous month to suggest that daily water changes have little affect on the growth rate. However, it seems that my choice of test fish was unfortunate. Royal resented the daily handling. He sulked a lot and would not eat as much as he had during the previous month. The experiment therefore is void. I may attempt this again with a betta with a more pliable personality.


Fry gender and water acidity: I received an email from someone who mentioned that when bettas spawn in acidic water, the resulting fry are mostly male. I plan to test this hypothesis by using PH Down with my next spawn to adjust the spawning tank's water to 6.6. This value is purely arbitrary. I will gradually get both the male and female used to acidic conditions by increasing the acidity of the water in their jars over a one month period.

This test should start in mid-May. The results will have to wait until the fry are old enough to be sexed, about August 1.


Wingless fruit flies as betta food: Mary Whitington Worth (MARY'S BETTA ROOM) sent me an email suggesting that I try raising and feeding flightless fruit flies to my bettas. I'd never heard of this before so I plan to give it a try. I'll be experimenting with culture mediums, collection techniques, and how well bettas accept the food.

I've raised fruit flies for experiments with hummingbirds (Please see my hummingbird pages, accessible from my home page.) and have seen a few flightless ones in the rearing chamber. Their size appears to be perfect for fry in the off-size stage where they are a too big for baby brine shrimp but too small for adult brine shrimp.

I hope to start this experiment as soon as I can obtain some flightless fruit fly culture from Mary. Expect results to be posted in early May.

I did and they ate them right up. The fruit flies tended to collect into a raft and seemedable to float for days. Breeding the flies was easy but to make them a daily part of the betta's diet would become tedious, sort of like having to start new brine shrimp cultures every day.


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