Platy Fish Keep Battling

???? Products used (Amazon affiliate links, avaible in GERMANY):
• vidaXL Aquarium Stand – Modern white cabinet with lots of storage space and a sturdy top plate for your aquarium setup: https://amzn.to/43MTinE
• Kärcher WD 3 P V-19/4/20 Wet & Dry Vacuum – Compact, powerful 1000 W cleaning solution with integrated socket for power tools: https://amzn.to/4qBliEH
• AquaForte Landscaping Foam (500 ml) – Expanding black pond foam perfect for rock and driftwood structures in aquascapes: https://amzn.to/3Lcy0JX
• Play Sand 25 kg Fine Quartz – Washed, germ-free decorative sand ideal for natural-looking substrates: https://amzn.to/3LlQYxz
• Floragard Pond & Aquatic Plant Soil 20 L – Nutrient-rich base soil for aquatic plants, lilies, and marginal species: https://amzn.to/4qCCklU
• EHEIM Experience 150 External Filter – Reliable, energy-efficient filtration system for crystal-clear water: https://amzn.to/47zEOJ1
• JBL ProScan Water Test Kit – Fast smartphone-based freshwater analysis for easy monitoring: https://amzn.to/3Li7ONR
• Aquarium Münster Orca Underwater Glue 75g, black: https://amzn.to/49cIeE8