This study was conducted to analyze the effect of rainwater on the survival of koi fry. The background of this study is based on the increasing demand for koi fish which encourages breeders to improve the quality and quantity of fry production. However, the success of seeding is influenced by several factors, especially air quality such as temperature and pH. Rainwater is known to have less stable quality, especially due to its low pH value, so it is necessary to study its impact on koi fry. This study was conducted on November 25–28, 2024 in the Bossbaster experimental pond, Legok Nyenang Village, Kadudampit District, Sukabumi Regency. The media used were 15 plastic gallons, each containing 5 liters of air and 40 newly hatched koi fry. The experimental design used a Completely Randomized Design (CRD) with 5 treatment levels and 3 replications. Treatments included A (100% rainwater), B (75% rainwater + 25% well water), C (50% rainwater + 50% well water), D (25% rainwater + 75% well water), and E (100% well water). The results of the ANOVA test showed that there was no significant difference (P>0.05) in the survival value of koi fish fry in the five treatments. Thus, it can be concluded that the use of rainwater does not have a significant effect on the survival of koi fish fry. In addition, the results of water quality observations showed that all parameters were still within the standard quality range, except for the temperature which was slightly below the standard.

Vertiqua biofical top filter is a cultivation technique with a recirculation system that utilizes limited land. Vertiqua is a solution for cultivation. When cultivating koi fish in vertiqua, the feed capacity increases and there is a high nutrient load so that the waters are easily polluted, therefore the presence of an upper biophysical filter can reduce pollution. This is important to study, especially the structure of the phytoplankton community because it is one of the biological indicators of ponds in koi fish cultivation. This research was carried out for 6 weeks in Sindangpalay Ciberem Sukabumi. The research was carried out by taking phytoplankton in the vertiqua at intervals of once every 2 weeks. The data analysis in this research is abundance, diversity, uniformity and dominance. During the research results obtained were abundance 636-673, diversity 2.6, uniformity 0.9, and dominance 0.01. The water quality studied was ammonia, nitrate, nitrite, phosphate, pH, DO, turbidity and temperature. These waters are stable and healthy, which is a positive indicator to support fish farming activities. The water quality in Vertiqua is classified as good and the ecosystem is balanced, these waters are ideal for supporting the productivity and health of farmed fish.

Vertiqua is an innovation in vertical cultivation on limited land and water. Vertiqua continues to be developed to be effective in cultivating fish. This research aims to examine the effectiveness of nitrogen distribution in vertiqua using biofical top filters. The analysis used is quantitative analysis by calculating and testing the data that has been collected. Total nitrogen feed input, total nitrogen wasted, and percentage of nitrogen absorption were calculated using existing formulas. Comparative testing using the T – test on the Mini Tab application was carried out to test the effectiveness of nitrogen absorption. The research results showed that nitrogen absorption in the vertiqua using the top biofical filter was effective, ranging from 198,12 – 200,89 mg/l. Nitrogen absorption in the vertiqua without using a biofical top filter ranges from 42,75 – 43,35 mg/l. The distribution value of effective nitrogen absorption in vertiqua using the top biofical filter is shown by a P value <0,05. Vertiqua with a biofical top filter is also able to reduce nitrogen levels so that fish survival is good.

The background of this research is that vertiqua is considered to have high production costs and small profits. Therefore, a business analysis is needed to increase the effectiveness of the fish farming business using the vertiqua system. The purpose of this study is to analyze the aquaculture business using the vertiqua system including capital and profit obtained. This research uses qualitative methods with descriptive explanations. The results of the research that has been done show that the R / C Ratio value obtained is 1.66, meaning that every 1 cycle cost expenditure will get 1.66 revenue. Koi fish farming using the vertiqua system is said to be feasible to continue because the R / C Ratio value is 1. The JWPM value with the calculation of 8 cycles for 1 year is 1.4, meaning that it takes 2 months and 2 days for the capital to return. Based on the business analysis conducted, the production of koi fish seeds using the upper biofical filter vertiqua system can be said to be feasible and has the potential to be further developed, because it can provide good profits with a good JWPM. In addition, cultivation using the upper biofical filter vertiqua system is very efficient in providing care for koi fish cultivation.
 
 

The growth of comet fish (Carassius auratus) in the vertiqua system using a biofical filter is motivated by limited land and water which can cause low water quality to affect the growth rate of fish. The utilization of technology needs to be done to overcome these problems and the technology used is vertiqua. Previous research showed that comet fish in the vertiqua system produced slow growth rates and had high ammonia levels. Therefore, vertiqua was modified in the filter section to become a biofical filter. The purpose of this research is to test the effectiveness of comet fish growth in the vertiqua system using a biofical filter. The benefits of this research are that the vertiqua system using a biofical filter can be a solution to overcome the problem of limited land and water, become a support for system cultivation innovation, and become a reference for further research. This research method uses descriptive methods, observation and interviews. The comet fish used in the study were 3-4 cm in size. The results of this study indicate that the vertiqua system using a biofical filter is still not effective in supporting fish growth. The growth rate of comet fish in the vertiqua system is significantly different from that in the soil pond and the growth rate of comet fish in the vertiqua system is lower than that of comet fish in the soil pond. Ammonia value is relatively high from the quality standard (>0.05). However, this system is able to maintain good fish survival and good water quality, especially in temperature, pH, and DO.