This comprehensive guide explores cryptocurrency price volatility, focusing on Bitcoin and Ethereum fluctuation analysis for 2026. It examines historical multi-year cycles showing Bitcoin's dramatic rise to near $69,000 with unprecedented low 2025 volatility of 2.24%, and Ethereum's maturation from $0.75 to $2,553. The article details support-resistance identification using technical indicators, BTC-ETH correlation dynamics revealing synchronized movements during market stress, and advanced GARCH volatility modeling for risk assessment. Practical guidance covers trading strategies on Gate, portfolio management techniques, and investor responses to market fluctuations. Key insights include 2026 price forecasts (Bitcoin $75,000-$225,000, Ethereum $2,475-$3,933), institutional adoption effects, and risk mitigation through diversification and disciplined position sizing.