Growth Rates

How come my shrimps aren’t breeding as much? Why are they staying small? These are reasonable questions that are related to the growth rates of shrimps.

Arbitrary example of shrimp growth over time for illustration purposes

Factors that influence or inhibit shrimp growth and breeding include:

  • Temperature
  • Water quality –> Nitrates & other elements which should be kept at or below 0.25 ppm and can be regulated through frequent water changes, filtration/ plant uptake
  • Tank size
  • Pheromones
  • Diet
  • Genetics
  • Nutrients

Temperature can lead to better yields in terms of babies or size, generally the higher the temperature around 26*C, the more breeding tends to occur, of course if the other conditions such as food, supplements etc. are met. Now on the other spectrum, the lower the temperature about 18*C the larger the shrimps will get reaching maturity. Of course, if we go to the extremes, say, reaching 30*C the breeding can only increase by so much before the number of mortalities start occurring. The optimal range that most breeders keep their shrimps at is 20 – 24*C (goldilocks zone). 

Water quality does not necessarily mean clean, a lot of beginners think clean/ clear is good but, when I refer to water quality I mean that its ideal for the shrimp type kept, so this can refer to pH, ammonia, nitrites, nitrates, GH etc. The water being green, brown, or murky does not necessarily mean the water quality is low but can be indicators of other factors. The parameters do not have to be precise and right on value. Having stable water qualities that are at the ideal range is best, with water changes to reduce the contents in the water when it exceeds those ranges (maintaining that ideal range). ‘A saying that you can use is aim small miss small’ – American Sniper.

Tank size is not necessarily the cause of the lack of shrimp growth, rather it is a constraint, the population size is usually the core problem. In a smaller aquarium the shrimps are less likely to be frequently berried, why you may ask? Well one reason is as stated above, the pheromones are released in higher concentration (due to already established, high population), hence the likelihood of a berry drought. The pheromones secreted are trapped and signal the other shrimps inhabiting the tank to stop breeding and slow down growth. A simple solution is dilution, because water changes remove the pheromones, and with lower concentration of the pheromones, it will signal other shrimps to kickstart breeding again. They will be like hey, we need to get it on. 

My hypothesis on this is that pheromones act as a control measure for population and is even applicable for other animals along with many other factors. But, ultimately water quality and tank size can restrict shrimp growth and breeding, manipulating the other variables and doing water changes when things get out of hand is best. 

Protein is also a crucial component in producing more berries (egg bound), why? Well the shrimp eggs require a lot of protein as well as other minerals in conjunction with ideal parameters to form. Think of it like this, if you can’t feed yourself, how would you feed your kid; speaking for pregnant mothers. This case is also true for shrimps too in a way, if there is a stable source of protein, or an abundance of food (biofilm), the shrimps are more likely to be saddled, then berried. Some of the shrimp foods that I have tested include Alan Hanzo HWA & munchies, New Life Spectrum Invertebrates, Shrimp Nature Nettle & Spinach, bloodworms. Feeding a diverse range of foods that contain other essential elements is also pivotal in increasing pregnant shrimp rates.

Another obvious factor includes genetics, not all shrimps have the genes to reproduce like Tangerine Tigers, or to be as vibrant in colour. The common ornamental varieties that are kept tend to be on the small size, reaching up to 3cm depending on conditions. This is also true for breeding, some shrimps will breed more frequently, mature earlier and subsequently begin breeding sooner, and some may carry more eggs per batch. These are all mostly genetics based with some environmental influence that can enhance or inhibit these characteristics.

Supplementing macro and/or micro (trace) elements for shrimps in a planted tank is also beneficial as it introduces necessary elements into the tank, of course not in high doses. I recommend fine tuning the dosage, perhaps lean dosing, but of course the amount of plants and how long the lights are on will impact your dosing. This aspect is also a branch of water quality, meaning that the water is stable whilst having the necessary elements for growth and breeding. 

Overall, these variables can be adjusted to meet your aquarium needs, maybe you’re after maximum breeding, manipulating temperatures, pheromones, and supplementing quality food is what your after. Whatever you’re after, I hope this has helped and provided you with a stronger understanding of how the mechanisms work and of course how you can optimise it